Causes of World War II

For broader coverage of this topic, see Diplomatic history of World War II.

During the Battle of Westerplatte, the German battleship Schleswig-Holstein attacks Westerplatte at the start of the war, September 1, 1939 The destroyer USS Shaw explodes during the attack on Pearl Harbor, December 7, 1941 Events leading to World War II

1910s

* Treaty of Versailles 1919
* Treaty of Saint-Germain-en-Laye 1919
* Polish–Soviet War 1919–1920
* Polish–Lithuanian War 1919–1920

1920s

* Treaty of Trianon 1920
* Treaty of Rapallo 1920
* Franco-Polish alliance 1921
* March on Rome 1922
* Corfu incident 1923
* Occupation of the Ruhr 1923–1925
* Mein Kampf 1925
* Second Italo-Senussi War 1923–1932
* Dawes Plan 1924
* Locarno Treaties 1925
* Young Plan 1929
* Great Depression 1929

1930s

* Japanese invasion of Manchuria 1931
* Pacification of Manchukuo 1931–1942
* January 28 incident 1932
* Geneva Conference 1932–1934
* Defense of the Great Wall 1933
* Battle of Rehe 1933
* Nazis' rise to power in Germany 1933
* Tanggu Truce 1933
* Italo-Soviet Pact 1933
* Inner Mongolian Campaign 1933–1936
* German–Polish declaration of non-aggression 1934
* Franco-Soviet Treaty of Mutual Assistance 1935
* Soviet–Czechoslovakia Treaty of Mutual Assistance 1935
* He–Umezu Agreement 1935
* Anglo-German Naval Agreement 1935
* December 9th Movement
* Second Italo-Ethiopian War 1935–1936
* Remilitarization of the Rhineland 1936
* Arab revolt in Palestine 1936–1939
* Spanish Civil War 1936–1939
* Italo-German "Axis" protocol 1936
* Anti-Comintern Pact 1936
* Suiyuan campaign 1936
* Xi'an Incident 1936
* Second Sino-Japanese War 1937–1945
* USS Panay incident 1937
* Anschluss Mar. 1938
* Polish ultimatum to Lithuania Mar. 1938
* May Crisis May 1938
* Battle of Lake Khasan July–Aug. 1938
* Bled Agreement Aug. 1938
* Undeclared German–Czechoslovak War Sep. 1938
* Munich Agreement Sep. 1938
* First Vienna Award Nov. 1938
* German occupation of Czechoslovakia Mar. 1939
* Hungarian invasion of Carpatho-Ukraine Mar. 1939
* German ultimatum to Lithuania Mar. 1939
* Slovak–Hungarian War Mar. 1939
* Final offensive of the Spanish Civil War Mar.–Apr. 1939
* Danzig Crisis Mar.–Aug. 1939
* British guarantee to Poland Mar. 1939
* Italian invasion of Albania Apr. 1939
* Soviet–British–French Moscow negotiations Apr.–Aug. 1939
* Pact of Steel May 1939
* Battles of Khalkhin Gol May–Sep. 1939
* Molotov–Ribbentrop Pact Aug. 1939
* Invasion of Poland Sep. 1939

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The causes of World War II have been given considerable attention by historians. The immediate precipitating event was the invasion of Poland by Nazi Germany on September 1, 1939, and the subsequent declarations of war on Germany made by Britain and France, but many other prior events have been suggested as ultimate causes. Primary themes in historical analysis of the war's origins include the political takeover of Germany in 1933 by Adolf Hitler and the Nazi Party; Japanese militarism against China, which led to the Japanese invasion of Manchuria and the Second Sino-Japanese War; Italian aggression against Ethiopia, which led to the Second Italo-Ethiopian War; or military uprising in Spain, which led to the Spanish Civil War.

During the interwar period, deep anger arose in the Weimar Republic over the conditions of the 1919 Treaty of Versailles, which punished Germany for its role in World War I with heavy financial reparations and severe limitations on its military that were intended to prevent it from becoming a military power again. The demilitarisation of the Rhineland, the prohibition of German unification with Austria, and the loss of its overseas colonies as well as some 12% of its pre-war land area and population all provoked strong currents of revanchism in German politics.

During the worldwide economic crisis of the Great Depression in the 1930s, many people lost faith in liberal democracy and countries across the world turned to authoritarian regimes.[1] In Germany, resentment over the terms of the Treaty of Versailles was intensified by the instability of the German political system, as many on both the Right and the Left rejected the Weimar Republic liberalism. The most extreme political aspirant to emerge from that situation was Adolf Hitler, the leader of the Nazi Party. The Nazis took totalitarian power in Germany from 1933 and demanded the undoing of the Versailles provisions. Their ambitious and aggressive domestic and foreign policies reflected their ideologies of antisemitism, unification of all Germans, the acquisition of "living space" (Lebensraum) for agrarian settlers, the elimination of Bolshevism and the hegemony of an "Aryan"/"Nordic" master race over "subhumans" (Untermenschen) such as Jews and Slavs. Other factors leading to the war included the aggression by Fascist Italy against Ethiopia, militarism in Imperial Japan against China, and Nationalists fighting against Republicans for control of Spain.

At first, the aggressive moves met with only feeble and ineffectual policies of appeasement from the other major world powers. The League of Nations proved helpless, especially regarding China and Ethiopia. A decisive proximate event was the 1938 Munich Conference, which formally approved Germany's annexation of the Sudetenland from Czechoslovakia. Hitler promised it was his last territorial claim, nevertheless in early 1939, he became even more aggressive, and European governments finally realised that appeasement would not guarantee peace but by then it was too late.

Britain and France rejected diplomatic efforts to form a military alliance with the Soviet Union, and Hitler instead offered Stalin a better deal in the Molotov–Ribbentrop Pact of August 1939. An alliance formed by Germany, Italy, and Japan led to the establishment of the Axis powers.

## Ultimate causes

[edit]

Further information: International relations (1919–1939)

### Legacies of World War I

[edit]

Further information: Aftermath of World War I and Treaty of Versailles

"The Big Four" made all the major decisions at the Paris Peace Conference (from left to right, David Lloyd George of Britain, Vittorio Emanuele Orlando of Italy, Georges Clemenceau of France, Woodrow Wilson of the U.S.)

By the end of World War I in late 1918, the world's social and geopolitical circumstances had fundamentally and irrevocably changed. The Allies had been victorious, but many of Europe's economies and infrastructures had been devastated, including those of the victors. France, along with the other victors, was in a desperate situation regarding its economy, security and morale and understood that its position in 1918 was "artificial and transitory".[2] Thus, French Prime Minister Georges Clemenceau worked to gain French security via the Treaty of Versailles, and French security demands, such as reparations, coal payments, and a demilitarised Rhineland, took precedence at the Paris Peace Conference of 1919–1920,[2] which designed the treaty. The war "must be someone's fault – and that's a very natural human reaction", analysed the historian Margaret MacMillan.[3] Germany was made to accept liability for the harm done to the Allies during World War I, and the War Guilt Clause was the basis for reparations to be paid to the Allies, especially France, by Germany. Roy H. Ginsberg argued, "France was greatly weakened and, in its weakness and fear of a resurgent Germany, sought to isolate and punish Germany... French revenge would come back to haunt France during the Nazi invasion and occupation twenty years later".[4]

Germany after Versailles

* * *

Administered by the League of Nations

Annexed or transferred to neighbouring countries by the treaty or later by plebiscites and League of Nation actions

Weimar Germany

The two main provisions of the French security agenda were war reparations from Germany, to be paid in gold and coal and a detached German Rhineland. The German (Weimar Republic) government printed excess currency, which created inflation, and it borrowed money from the United States. Reparations from Germany were needed to stabilise the French economy.[5] France also demanded for Germany to give France its coal supply from the Ruhr to compensate for the destruction of French coal mines during the war. France also insisted on the demilitarisation of the German Rhineland in the hope of hindering any possibility of a future German attack and giving France a physical security barrier between itself and Germany.[6] The payment of reparations, and the principle of a demilitarised Rhineland, were largely viewed by the Germans as insulting and unreasonable.

The resulting Treaty of Versailles brought a formal end to the war but was judged by governments on all sides of the conflict. It was criticised as neither lenient enough to appease Germany nor harsh enough to prevent it from becoming a dominant continental power again.[7] The German people largely viewed the treaty as placing the blame, or "war guilt", on Germany and Austria-Hungary and as punishing them for their "responsibility", rather than working out an agreement that would assure long-term peace. The treaty imposed harsh monetary reparations and requirements for demilitarisation and territorial dismemberment, caused mass ethnic resettlement and separated millions of ethnic Germans into neighbouring countries.

Already, during the First World War, inflation had become a serious problem for Germany. The Weimar Republic then printed trillions of marks, much of which went to pay workers striking against French occupation in the Ruhr or to pay back (or otherwise reduce the burden of) domestic wartime debt without raising taxes, which caused hyperinflation.[8]: 237  Hyperinflation further served to discredit the Weimar government. Adolf Hitler, a leader of the Nazi Party, attempted a coup d'état in 1923 in what became known as the Beer Hall Putsch, and he intended to establish a Greater Germanic Reich.[9] Although he failed, Hitler gained recognition as a national hero by the German population.

During the war, German colonies outside Europe had been annexed by the Allies, and Italy took the southern half of Tyrol after the armistice. The war in the east had ended with the defeat and the collapse of the Russian Empire, and German troops had occupied large parts of Eastern and Central Europe with varying degrees of control and established various client states such as a kingdom of Poland and the United Baltic Duchy. The German Navy spent most of the war in port, only to be turned over to the Allies. It was scuttled by its own officers to avoid it from being surrendered. The lack of an obvious military defeat would become one of the pillars holding together the Dolchstosslegende ("stab-in-the-back myth"), which gave the Nazis another propaganda tool.

Map of territorial changes in Europe after World War I (as of 1922)

The demilitarised Rhineland and the additional cutbacks on military also infuriated the Germans. Although France logically wanted the Rhineland to be a neutral zone, France had the power to make their desire happen, which merely exacerbated German resentment of the French. In addition, the Treaty of Versailles dissolved the German general staff, and possession of navy ships, aircraft, poison gas, tanks and heavy artillery was also made illegal.[6] The humiliation of being bossed around by the victor countries, especially France, and being stripped of their prized military made the Germans resent the Weimar Republic and idolise anyone who stood up to it.[10] Austria also found the treaty unjust, which encouraged Hitler's popularity.

The conditions generated bitter resentment towards the war's victors, who had promised the Germans that US President Woodrow Wilson's Fourteen Points would be a guideline for peace; but the Americans had played only a minor role in the war, and Wilson could not convince the Allies to agree to adopt his Fourteen Points. Many Germans felt that the German government had agreed to an armistice based on that understanding, and others felt that the German Revolution of 1918–1919 had been orchestrated by the "November criminals", who later assumed office in the new Weimar Republic. The Japanese also started to express resentment against Western Europe for how they were treated during the negotiations of the Treaty of Versailles. The Japanese proposition to discuss the issue of racial equality was not put in the final draft because of many other Allies, and the Japanese participation in the war caused little reward for the country.[11] The war's economic and psychological legacies persisted well into the Interwar period.

### Failure of the League of Nations

[edit]

The League of Nations was an international peacekeeping organization founded in 1919 with the explicit goal of preventing future wars.[12] The League's methods included disarmament, collective security, the settlement of disputes between countries by negotiations and diplomacy and the improvement of global welfare. The diplomatic philosophy behind the League represented a fundamental shift in thought from the preceding century. The old philosophy of "concert of nations", which grew out of the Congress of Vienna (1815), saw Europe as a shifting map of alliances among nation-states, which created a balance of power that was maintained by strong armies and secret agreements. Under the new philosophy, the League would act as a government of governments, with the role of settling disputes between individual nations in an open and legalist forum. Despite Wilson's advocacy, the United States never joined the League of Nations.

The League lacked an armed force of its own and so depended on member nations to enforce its resolutions, uphold economic sanctions that the League ordered or provide an army when needed for the League to use. However, individual governments were often very reluctant to do so. After numerous notable successes and some early failures in the 1920s, the League ultimately proved incapable of preventing aggression by the Axis Powers in the 1930s. The reliance upon unanimous decisions, the lack of an independent body of armed forces and the continued self-interest of its leading members meant that the failure was arguably inevitable.[13][14]

### Expansionism and militarism

[edit]

Further information: Italian irredentism, Weimar Republic, Statism in Shōwa Japan, and Japanese militarism

Expansionism is the doctrine of expanding the territorial base or economic influence of a country, usually by means of military aggression. Militarism is the principle or policy of maintaining a strong military capability to use aggressively to expand national interests and/or values, with the view that military efficiency is the supreme ideal of a state.[15]

The Treaty of Versailles and the League of Nations had sought to stifle expansionist and militarist policies by all actors, but the conditions imposed by their creators imposed on the world's new geopolitical situation and the technological circumstances of the era only emboldened the re-emergence of those ideologies during the Interwar Period. By the early 1930s, militaristic and aggressive national ideologies prevailed in Germany, Japan and Italy.[16] The attitude fuelled advancements in military technology, subversive propaganda and ultimately territorial expansion. It has been observed that the leaders of countries that have been suddenly militarised often feel a need to prove that their armies are formidable, which was often a contributing factor in the start of conflicts such as the Second Italo-Ethiopian War and the Second Sino-Japanese War.[17]

Italy and its colonial possessions in 1940

In Italy, Benito Mussolini sought to create a New Roman Empire, based around the Mediterranean. Italy invaded Ethiopia as early as 1935, Albania in early 1938, and later Greece. The invasion of Ethiopia provoked angry words and a failed oil embargo from the League of Nations. Spazio vitale ("living space") was the territorial expansionist concept of Italian Fascism. It was analogous to Nazi Germany's concept of Lebensraum and the United States' concept of "Manifest Destiny". Fascist ideologist Giuseppe Bottai likened this historic mission to the deeds of the ancient Romans.[18]

Under the Nazi regime, Germany began its own program of expansion that sought to restore its "rightful" boundaries. As a prelude toward its goals, the Rhineland was remilitarised in March 1936.[19] Also of importance was the idea of a Greater Germany, supporters of which hoped to unite the German people under one nation-state to include all territories inhabited by Germans, even if they happened to be a minority in a particular territory. After the Treaty of Versailles, a unification between Germany and the newly formed German-Austria, a rump state of Austria-Hungary, was blocked by the Allies, despite the large majority of Austrians supporting the idea.

During the Weimar Republic (1919–1933), the Kapp Putsch, an attempted coup d'état against the republican government, was launched by disaffected members of the armed forces. Later, some of the more radical militarists and nationalists were submerged in grief and despair into the Nazi Party, and more moderate elements of militarism declined. The result was an influx of militarily-inclined men into the Nazi Party. Combined with its racial theories, that fuelled irredentist sentiments and put Germany on a collision course for war with its immediate neighbours.

The Japanese march into Zhengyangmen, Beijing, after they captured the city in July 1937

In Asia, the Empire of Japan harboured expansionist desires towards Manchuria and the Republic of China. Two contemporaneous factors in Japan contributed both to the growing power of its military and the chaos in its ranks before World War I. One was the Cabinet Law, which required the Imperial Japanese Army (IJA) and the Imperial Japanese Navy (IJN) to nominate cabinet members before changes could be formed. That essentially gave the military a veto power over the formation of any Cabinet in the ostensibly-parliamentary country. The other factor was gekokujō, the institutionalized disobedience by junior officers. It was common for radical junior officers to press their goals to the extent of assassinating their seniors. In 1936, the phenomenon resulted in the February 26 Incident in which junior officers attempted a coup d'état and killed leading members of the Japanese government. In the 1930s, the Great Depression wrecked Japan's economy and gave radical elements within the Japanese military the chance to force the entire military into working towards the conquest of all of Asia.

For example, in 1931, the Kwantung Army, a Japanese military force stationed in Manchuria, staged the Mukden Incident, which sparked the invasion of Manchuria and its transformation into the Japanese puppet state of Manchukuo.

### Germans vs. Slavs

[edit]

Further information: Racial policy of Nazi Germany, Lebensraum, and Drang nach Osten

Twentieth-century events marked the culmination of a millennium-long process of intermingling between Germans and Slavic people. The rise of nationalism in the 19th century made race a centerpiece of political loyalty. The rise of the nation-state had given way to the politics of identity, including pan-Germanism and pan-Slavism. Furthermore, Social Darwinist theories framed the coexistence as a "Teuton vs. Slav" struggle for domination, land, and limited resources.[20] Integrating these ideas into their own worldview, the Nazis believed that the Germans, the "Aryan race", were the master race and that the Russians and Poles were inferior.[21]

### Japan's seizure of resources and markets

[edit]

Japanese occupation of China in 1937

Other than a few coal and iron deposits and a small oil field on Sakhalin Island, Japan lacked strategic mineral resources. In the early 20th century, in the Russo-Japanese War, Japan had succeeded in pushing back the East Asian expansion of the Russian Empire in competition for Korea and Manchuria.

Japan's goal after 1931 was economic dominance of most of East Asia, often expressed in the Pan-Asian terms of "Asia for the Asians".[22] Japan was determined to dominate the China market, which the US and other European powers had been dominating. On October 19, 1939, US Ambassador to Japan Joseph C. Grew, in a formal address to the America-Japan Society, stated that

> the new order in East Asia has appeared to include, among other things, depriving Americans of their long established rights in China, and to this the American people are opposed.... American rights and interests in China are being impaired or destroyed by the policies and actions of the Japanese authorities in China.[23]

In 1931, Japan invaded Manchuria and China proper. Under the guise of the Greater East Asia Co-Prosperity Sphere, with slogans such as "Asia for the Asians!", Japan sought to remove the Western powers' influence in China and replace it with Japanese domination.[24][25]

The ongoing conflict in China led to a deepening conflict with the US in which public opinion was alarmed by events such as the Nanking Massacre and growing Japanese power. Lengthy talks were held between the US and Japan. The Japanese invasion of the south of French Indochina made President Franklin Roosevelt freeze all Japanese assets in the US. The intended consequence was to halt oil shipments from the US to Japan, which supplied 80 percent of Japanese oil imports. The Netherlands and Britain followed suit.

With oil reserves that would last only a year and a half during peacetime and much less during wartime, the ABCD line left Japan two choices: comply with the US-led demand to pull out of China or seize the oilfields in the East Indies from the Netherlands. The Japanese government deemed it unacceptable to retreat from China.[26]

### Mason-Overy debate: "Flight into War" theory

[edit]

In the late 1980s, the British historian Richard Overy was involved in a historical dispute with Timothy Mason that played out mostly over the pages of the Past and Present journal over the reasons for the outbreak of the war in 1939. Mason had contended that a "flight into war" had been imposed on Hitler by a structural economic crisis, which confronted Hitler with the choice of making difficult economic decisions or aggression. Overy argued against Mason's thesis by maintaining that Germany was faced with economic problems in 1939, but the extent of those problems could not explain aggression against Poland and the reasons for the outbreak of war were the choices made by the Nazi leadership.

Mason had argued that the German working-class was always against the Nazi dictatorship; that in the overheated German economy of the late 1930s, German workers could force employers to grant higher wages by leaving for another firm and so grant the desired wage increases and that such a form of political resistance forced Hitler to go to war in 1939.[27] Thus, the outbreak of the war was caused by structural economic problems, a "flight into war" imposed by a domestic crisis.[27] The key aspects of the crisis were, according to Mason, a shaky economic recovery that was threatened by a rearmament program that overwhelmed the economy and in which the regime's nationalist bluster limited its options.[27] In that way, Mason articulated a Primat der Innenpolitik ("primacy of domestic politics") view of the war's origins by the concept of social imperialism.[28] Mason's Primat der Innenpolitik thesis was in marked contrast to the Primat der Außenpolitik ("primacy of foreign politics"), which is usually used to explain the war.[27] Mason thought German foreign policy was driven by domestic political considerations, and the launch the war in 1939 was best understood as a "barbaric variant of social imperialism".[29]

Mason argued, "Nazi Germany was always bent at some time upon a major war of expansion".[30] However, Mason argued that the timing of such a war was determined by domestic political pressures, especially as relating to a failing economy, and had nothing to do with what Hitler wanted.[30] Mason believed that from 1936 to 1941, the state of the German economy, not Hitler's "will" or "intentions", was the most important determinate on German foreign policy decisions.[31]

Mason argued that the Nazi leaders were so deeply haunted by the November 1918 German Revolution that they were most unwilling to see any fall in working-class living standards for fear of provoking a repetition of the revolution.[31] Mason stated that by 1939, the "overheating" of the German economy caused by rearmament, the failure of various rearmament plans produced by the shortages of skilled workers, industrial unrest caused by the breakdown of German social policies and the sharp drop in living standards for the German working class forced Hitler into going to war at a time and a place that were not of his choosing.[32]

Mason contended that when faced with the deep socio-economic crisis, the Nazi leadership had decided to embark upon a ruthless foreign policy of "smash and grab" to seize territory in Eastern Europe that could be pitilessly plundered to support the living standards in Germany.[33] Mason described German foreign policy as driven by an opportunistic "next victim" syndrome after the Anschluss in which the "promiscuity of aggressive intentions" was nurtured by every successful foreign policy move.[34] Mason's considered the decision to sign the Molotov–Ribbentrop Pact and to attack Poland despite the risk of a war against Britain and France to be the abandonment by Hitler of his foreign policy program outlined in Mein Kampf and to have been forced on him by his need to stop a collapsing German economy by seizing territory abroad to be plundered.[32]

For Overy, the problem with Mason's thesis was that it rested on the assumption that in a way that was not shown by the records, information was passed on to Hitler about Germany's economic problems.[35] Overy argued for a difference between economic pressures induced by the problems of the Four Year Plan and economic motives to seize raw materials, industry and foreign reserves of neighbouring states as a way of accelerating the plan.[36] Overy asserted that Mason downplayed the repressive German state's capacity to deal with domestic unhappiness.[35] Finally, Overy argued that there is considerable evidence that Germany felt that it could master the economic problems of rearmament. As one civil servant put it in January 1940, "we have already mastered so many difficulties in the past, that here too, if one or other raw material became extremely scarce, ways and means will always yet be found to get out of a fix".[37]

## Proximate causes

[edit]

### Nazi dictatorship

[edit]

Further information: Nazi Germany and Nazi Party

Adolf Hitler in Bad Godesberg, Germany, 1938

Hitler and his Nazis took full control of Germany in 1933–34 (Machtergreifung), turning it into a dictatorship with a highly hostile outlook toward the Treaty of Versailles and Jews.[38] It solved its unemployment crisis by heavy military spending.[39]

Hitler's diplomatic tactics were to make seemingly-reasonable demands and to threaten war if they were not met. After concessions were made, he accepted them and moved onto a new demand.[40] When opponents tried to appease him, he accepted the gains that were offered and went to the next target. That aggressive strategy worked as Germany pulled out of the League of Nations (1933), rejected the Versailles Treaty, began to rearm with the Anglo-German Naval Agreement (1935), won back the Saar (1935), re-militarized the Rhineland (1936), formed an alliance ("axis") with Mussolini's Italy (1936), sent massive military aid to Franco in the Spanish Civil War (1936–39), seized Austria (1938), took over Czechoslovakia after the British and French appeasement of the Munich Agreement of 1938, formed a peace pact with Stalin's Russia in August 1939 and finally invaded Poland in September 1939.[41]

### Remilitarization of the Rhineland

[edit]

Main article: Remilitarization of the Rhineland

In violation of the Treaty of Versailles and the spirit of the Locarno Pact and the Stresa Front, Germany remilitarized the Rhineland on March 7, 1936, by moving German troops into the part of western Germany in which according to the Versailles Treaty, they were not allowed. Neither France nor Britain was prepared to fight a preventive war to stop the violation and so there were no consequences.[42]

### Italian invasion of Abyssinia

[edit]

Further information: Second Italo-Abyssinian War

Following the Stresa Conference and even as a reaction to the Anglo-German Naval Agreement, the Italian dictator Benito Mussolini attempted to expand the Italian Empire in Africa by invading the Ethiopian Empire, also known as the Abyssinian Empire. The League of Nations declared Italy to be the aggressor and imposed sanctions on oil sales, which proved ineffective. Italy annexed Ethiopia in May 1936 and merged Ethiopia, Eritrea and Somaliland into a single colony, known as Italian East Africa. On June 30, 1936, Ethiopian Emperor Haile Selassie gave a stirring speech before the League of Nations denouncing Italy's actions and criticizing the world community for standing by. He warned, "It is us today. It will be you tomorrow". As a result of the League's condemnation of Italy, Mussolini declared the country's withdrawal from the organization.[43]

### Spanish Civil War

[edit]

Further information: Spanish Civil War

Francisco Franco and Heinrich Himmler in Madrid, Spain, 1940

Between 1936 and 1939, Germany and Italy lent support to the Nationalists led by general Francisco Franco in Spain, and the Soviet Union supported the existing democratically elected government, the Spanish Republic, led by Manuel Azaña. Both sides experimented with new weapons and tactics. The League of Nations was never involved, and its major powers remained neutral and tried with little success to stop arms shipments into Spain. The Nationalists eventually defeated the Republicans in 1939.[44]

Spain negotiated with joining the Axis but remained neutral during World War II and did business with both sides. It also sent a volunteer unit to help the Germans against the Soviets. The Spanish Civil War was considered in the 1940s and 1950s to be a prelude to World War II, which was the case to some extent by changing it into an antifascist contest after 1941, but bore no resemblance to the war that started in 1939 and had no major role in causing it.[45][46]

### Second Sino-Japanese War

[edit]

Further information: Second Sino-Japanese War

In 1931, Japan took advantage of China's weakness in the Warlord Era and fabricated the Mukden Incident in 1931 to set up the puppet state of Manchukuo in Manchuria, with Emperor Puyi, who had been the last emperor of China. In 1937 the Marco Polo Bridge Incident triggered the Second Sino-Japanese War.

The invasion was launched by the bombing of many cities such as Shanghai, Nanjing and Guangzhou. The latest, which began on 22 and 23 September 1937, called forth widespread protests culminating in a resolution by the Far Eastern Advisory Committee of the League of Nations. The Imperial Japanese Army captured the Chinese capital city of Nanjing and committed war crimes in the Nanjing Massacre. The war tied down large numbers of Chinese soldiers and so Japan set up three different Chinese puppet states to enlist some Chinese support.[47]

### Anschluss

[edit]

Cheering crowds greet the Nazis in Innsbruck

The Anschluss was the 1938 annexation by threat of force of Austria into Germany. Historically, Pan-Germanism was the idea of creating a Greater Germany to include all ethnic Germans into one nation-state and was popular in both Austria and Germany.[48]

The National Socialist Program included the idea in one of its points: "We demand the unification of all Germans in the Greater Germany on the basis of the people's right to self-determination."

The Stresa Front of 1935 between Britain, France and Italy had guaranteed the independence of Austria, but after the creation of the Rome-Berlin Axis, Mussolini was much less interested in upholding its independence.

The Austrian government resisted as long as possible but had no outside support and finally gave in to Hitler's fiery demands. No fighting occurred, most Austrians supported the annexation and Austria was fully absorbed as part of Germany. Outside powers did nothing, and Italy had little reason for continued opposition to Germany and, if anything, was drawn in closer to the Nazis.[49][50]

### Munich Agreement

[edit]

Further information: Munich Agreement and Appeasement

The Sudetenland was a predominantly-German region in Czechoslovakia along the border with Germany. It had more than three million ethnic Germans, who comprised almost a quarter of the country's population. In the Treaty of Versailles, the region was given to the Czechoslovakia against the wishes of most of the local population. The decision to disregard its right to self-determination was based on France's intent to weaken Germany. Much of Sudetenland was industrialised.[49]

British Prime Minister Neville Chamberlain and Hitler at a meeting in Germany on 24 September 1938, and Hitler demanded the immediate annexation of Czechoslovak border areas.

Czechoslovakia had a modern army of 38 divisions, backed by a well-noted armament industry (Škoda) and military alliances with France and the Soviet Union. However, its defensive strategy against Germany was based on the mountains of the Sudetenland.

Hitler pressed for the Sudetenland's incorporation into Germany and supported German separatist groups within the region. Alleged Czechoslovak brutality and persecution under Prague helped to stir up nationalist tendencies, as did the Nazi press. After the Anschluss, all German parties except for the German Social-Democratic Party merged with the Sudeten German Party (SdP). Paramilitary activity and extremist violence peaked during the period, and the Czechoslovak government declared martial law in parts of the Sudetenland to maintain order. That only complicated the situation, especially since Slovak nationalism was rising from suspicion towards Prague and encouragement by Germany. Citing the need to protect the Germans in Czechoslovakia, Germany requested the immediate annexation of the Sudetenland.

In the Munich Agreement on September 30, 1938, the British, French, and Italian prime ministers appeased Hitler by giving him what he wanted in the hope that it would be his last demand. The powers allowed Germany to move troops into the region and incorporate it into the Reich "for the sake of peace". In exchange, Hitler gave his word that Germany would make no further territorial claims in Europe.[51] Czechoslovakia was not allowed to participate in the conference. When the French and British negotiators informed the Czechoslovak representatives about the agreement and that if Czechoslovakia would not accept it, France and Britain would consider Czechoslovakia to be responsible for war and stay neutral, Czechoslovak President Edvard Beneš capitulated and Germany took the Sudetenland unopposed.[52]

Chamberlain's policies have been the subject of intense debate for more than 70 years by academics, politicians and diplomats. The historians' assessments have ranged from condemnation for allowing Hitler's Germany to grow too strong to the judgment that Germany was so strong that it might well win a war and so the postponement of a showdown was in the country's best interests.[53]

#### German occupation and Slovak independence

[edit]

Further information: Occupation of Czechoslovakia (1938–1945), Protectorate of Bohemia-Moravia, and Slovak Republic (1939–1945)

All territories taken from Czechoslovakia by its neighbours in October 1938 ("Munich Dictate") and March 1939

In March 1939, breaking the Munich Agreement, German troops invaded Prague, and with the Slovaks declaring independence, Czechoslovakia disappeared as a country. The entire ordeal ended the French and British policy of appeasement.

### Italian invasion of Albania

[edit]

Further information: Italian invasion of Albania

After the German occupation of Czechoslovakia, Mussolini feared for Italy becoming a second-rate member of the Axis. Rome delivered Tirana an ultimatum on March 25, 1939, by demanding the accession to Italy's occupation of Albania. King Zog refused to accept money in exchange for allowing a full Italian takeover and colonization of Albania.

On April 7, 1939, Italian troops invaded Albania, which was occupied after a three-day campaign with minimal resistance offered by Albanian forces.

### Soviet–Japanese border war

[edit]

Further information: Battle of Khalkhin Gol

In 1939, the Japanese attacked west from Manchuria into the Mongolian People's Republic after the 1938 Battle of Lake Khasan. They were decisively beaten by Soviet units, under General Georgy Zhukov. After the battle, the Soviet Union and Japan were at peace until 1945. Japan looked south to expand its empire, which led to conflict with the United States over the Philippines and the control of shipping lanes to the Dutch East Indies. The Soviet Union focused on its western border but left 1 million to 1.5 million troops to guard its border with Japan.

### Danzig crisis

[edit]

The Polish Corridor and the Free City of Danzig

Further information: Free City of Danzig (interwar) and Polish Corridor

After the end of Czechoslovakia proved that Germany could not be trusted, Britain and France decided on a change of strategy. They decided any further unilateral German expansion would be met by force. The natural next target for German expansion was Poland, whose access to the Baltic sea had been carved out of West Prussia by the Versailles Treaty, which made East Prussia an exclave. The main port of the area, Danzig, had been made into a free city-state under Polish influence guaranteed by the League of Nations, a stark reminder to German nationalists of the Napoleonic free city that had been established after French Emperor Napoleon I's crushing victory over Prussia in 1807.

After taking power, the Nazi government made efforts to establish friendly relations with Poland, which resulted in the signing of the ten-year German–Polish Non-Aggression Pact with the Piłsudski regime in 1934. In 1938, Poland participated in the dismemberment of Czechoslovakia by annexing Trans-Olza. In 1939, Hitler claimed extraterritoriality for the Reichsautobahn Berlin-Königsberg and a change in Danzig's status in exchange for promises of territory in Poland's neighbours and a 25-year extension of the non-aggression pact. Poland refused for fear of losing its de facto access to the sea, subjugation as a German satellite state or client state and future further German demands.[54][55] In August 1939, Hitler delivered an ultimatum to Poland on Danzig's status.

#### Polish alliance with the Entente

[edit]

The Franco-Polish Alliance was the military alliance between Poland and France that was active between the early 1920s and the outbreak of the Second World War. The initial agreements were signed in February 1921 and formally took effect in 1923. During the interwar period the alliance with Poland was one of the cornerstones of French foreign policy.

The Anglo-Polish Alliance was formalised by the Anglo-Polish Agreement in 1939, with subsequent addenda of 1940 and 1944,[56] for mutual assistance in case of a military invasion from Nazi Germany, as specified in a secret protocol.[57][58][59]

## Interwar period

[edit]

During the Polish–Soviet War of 1920, France, one of the most active supporters of Poland, sent the French Military Mission to Poland to aid the Polish army. In early February in Paris, three pacts were discussed by Polish Chief of State Józef Piłsudski and French President Alexandre Millerand: political, military and economic.

The political alliance was signed there on February 19, 1921 by Polish Minister of Foreign Affairs Count Eustachy Sapieha and French Minister of Foreign Affairs Aristide Briand, in the background of the negotiations that ended the Polish–Soviet War by the Treaty of Riga. The agreement assumed a common foreign policy, the promotion of bilateral economical contacts, the consultation of new pacts concerning Central and Eastern Europe and assistance in case one of the signatories became a victim of an "unprovoked" attack. As such, it was a defensive alliance. The secret military pact was signed two days later, on February 21, 1921, and clarified that the agreement was aimed at possible threats from both Germany and the Soviet Union. An attack on Poland would make France keep lines of communication free and Germany in check but not require it to send troops or to declare war. Both political and military pacts were legally not in force until the economic pact was ratified, which occurred on August 2, 1923.

The alliance was further extended by the Franco–Polish Warrant Agreement, signed on October 16, 1925 in Locarno, as part of the Locarno Treaties. The new treaty subscribed all previously-signed Polish–French agreements to the system of mutual pacts of the League of Nations.

The alliance was closely tied with the Franco-Czechoslovak Alliance. France's alliances with Poland and Czechoslovakia were aimed at deterring Germany from the use of force to achieve a revision of the postwar settlement and ensuring that German forces would be confronted with significant combined strength of its neighbours. Although Czechoslovakia had a significant economy and industry and Poland had a strong army, the French–Polish–Czechoslovak triangle never reached its full potential. Czechoslovak foreign policy, under Edvard Beneš, avoided signing a formal alliance with Poland, which would force Czechoslovakia to take sides in Polish–German territorial disputes. Czechoslovakia's influence was weakened by the doubts of its allies as to the trustworthiness of its army, and Poland's influence was undermined by fighting between supporters and opponents of Józef Piłsudski. France's reluctance to invest in its allies' industry (especially Poland's), improve trade relations by buying their agricultural products and share military expertise further weakened the alliance.

In the 1930s, the alliance remained mostly inactive and its only effect was to keep the French Military Mission to Poland, which had worked with the Polish General Staff ever since the Polish–Soviet War of 1919–1920. However, with the German threat becoming increasingly visible in the latter part of the decade, both countries started to seek a new pact to guarantee the independence of all contracting parties and military co-operation in case of a war with Germany.

## 1939

[edit]

See also: Anglo-Polish alliance

Finally, a new alliance started to be formed in 1939. The Kasprzycki–Gamelin Convention was signed May 19, 1939 in Paris. It was named after Polish Minister of War Affairs General Tadeusz Kasprzycki and Commander of the French Army Maurice Gamelin.[60] The military convention was army-to-army, not state-to-state, and was not in force legally, as it was dependent on signing and ratification of the political convention. It obliged both armies to provide help to each other in case of a war with Germany. In May, Gamelin promised a "bold relief offensive" within three weeks of a German attack.

Despite the French government's ratification of the treaty on 4 September 1939, four days after Germany invaded Poland, the promised military support was minimal. France's limited engagement, known as the Saar Offensive, involved a brief incursion into German territory but lacked significant impact and was soon halted. This tepid response has been cited as an example of Western betrayal. Nevertheless, the political convention facilitated the reformation of the Polish Army on French soil.

French Ambassador to Poland, Léon Noël, expressed skepticism about France's commitments. In October 1938, he noted the importance of maintaining France's freedom of decision in the event of a Polish-German conflict. Foreign Minister Georges Bonnet echoed this sentiment, emphasizing the intentional vagueness of the agreement to avoid obligating France to war.

In response to escalating tensions, Britain and France guaranteed Poland's independence in March 1939. Subsequently, on 15 August 1939, Britain and Poland formalized their alliance through the Anglo-Polish Agreement of Mutual Assistance. This pact committed both nations to support each other in the event of a German attack. A secret protocol clarified that the agreement specifically addressed German aggression, not potential threats from other nations.[61][62]

### Molotov–Ribbentrop Pact

[edit]

Germany invaded Poland on 1 September 1939 which directly led to the Anglo-French declaration of war on Germany on 3 September. The Soviet Union joined Germany's invasion of Poland on 17 September.

Further information: Molotov–Ribbentrop Pact, Soviet invasion of Poland, Occupation of the Baltic states, Soviet occupation of Bessarabia and Northern Bukovina, and Winter War

Nominally, the Molotov–Ribbentrop Pact was a non-aggression treaty between Germany and the Soviet Union and was signed in Moscow on August 23, 1939, by Soviet Foreign Minister Vyacheslav Molotov and German Foreign Minister Joachim von Ribbentrop.

In 1939, neither Germany nor the Soviet Union was ready to go to war with each other. The Soviet Union had lost territory to Poland in 1920. Although officially called a "non-aggression treaty," the pact included a secret protocol in which the independent countries of Finland, Estonia, Latvia, Lithuania, Poland and Romania were divided into spheres of interest between both the parties.[63] The secret protocol explicitly assumed "territorial and political rearrangements" in those areas.[64]

Germany invaded Poland on 1 September 1939, prompting Britain and France to declare war on Germany two days later.[65][66] On 17 September the Soviet Union invaded eastern Poland, citing the need to protect ethnic Ukrainians and Belarusians. These coordinated invasions effectively dismantled the Polish state.[67][68]

## Declarations of war

[edit]

### Invasion of Poland

[edit]

Further information: Invasion of Poland

Grave of German soldiers fallen during invasion of Poland in Końskie. Visible inscription "Für Führer und Vaterland"

Between 1919 and 1939, Poland had pursued a policy of balancing between the Soviet Union and Nazi Germany and agreed to non-aggression pacts with both.[69] In early 1939, Germany demanded for Poland to join the Anti-Comintern Pact as a satellite state of Germany.[70] Poland, fearing a loss of independence, refused. Hitler admitted to his generals on 23 May 1939 that his reason for invading Poland was not Danzig: "Danzig is not the issue at stake. It is a matter of extending our living space in the East...".[71] To deter Hitler, Britain and France announced that an invasion would mean war and tried to convince the Soviet Union to join in this deterrence. The Soviets, however, gained control of the Baltic states and part of Poland by allying with Germany by the secret Molotov–Ribbentrop Pact in August 1939. London's attempt at deterrence failed, but Hitler did not expect a wider war. Germany invaded Poland on September 1, 1939, and rejected the British and French demands for it to withdraw, which resulted in both to declare war on September 3, 1939, in accordance with the defence treaties with Poland that they had signed and publicly announced.[72][73] However neither France nor Britain provided significant military aid to Poland except small operation known as Saar offensive. As of 1 September 1939 Poland was only partially mobilized, which was largely the result of pressure from the British and French ambassadors on the Polish government, fearing a repeat of the mobilization scenario of war from 1914. The Wehrmacht also had advantage in terms of the number of tanks and planes and the technical advancement of its equipment.[citation needed]

On September 17, 1939, the Red Army entered Poland from the east, and the Polish Command decided to abandon the defense of the so-called Romanian Bridgehead and evacuate of all its forces to neighboring countries. The last larger unit of Polish troops capitulated on October 6, 1939, near Kock, but some units went straight to partisan combat. Until the spring of 1940, the resistance of irregular units in the region of the Świętokrzyskie Mountains in central Poland lasted, but the struggle of these units resulted in enormous repressions against the civilian population of the region in which they operated.[citation needed]

### Invasion of the Soviet Union

[edit]

Further information: Operation Barbarossa and Soviet offensive plans controversy

Germany attacked the Soviet Union in June 1941. Hitler believed that the Soviet Union could be defeated in a fast and relentless assault that capitalised on the Soviets' ill-prepared state and he hoped that his success there would bring Britain to the negotiating table, an event which would end the war altogether.

### Attacks on Pearl Harbor, the Philippines, British Malaya, Singapore and Hong Kong

[edit]

Further information: Prelude to the attack on Pearl Harbor

The US government and general public in general had been supportive of China, condemned European colonialist policies and Japan and promoted the so-called Open Door Policy. Many Americans viewed the Japanese as an aggressive and/or inferior race. The Nationalist government of Chiang Kai-shek held friendly relations with the US, which opposed Japan's invasion of China in 1937 and considered it a violation of international law and of the sovereignty of the Republic of China. The US offered the Nationalist government diplomatic, economic and military assistance during its war against Japan. Diplomatic friction between the United States and Japan manifested itself in events like the Panay incident in 1937 and the Allison incident in 1938.

Japanese troops entering Saigon

Reacting to Japanese pressure on French authorities of French Indochina to stop trade with China, the US began restricting trade with Japan in July 1940. The end of all oil shipments in 1941 was decisive since the Americans, British and Dutch provided almost all of Japan's oil.[74] In September 1940, the Japanese invaded Vichy French Indochina and occupied Tonkin to prevent China from importing arms and fuel through French Indochina along the Sino-Vietnamese Railway from the port of Haiphong through Hanoi to Kunming, in Yunnan.[75] The US decided that the Japanese had now gone too far and decided to force a rollback of its gains.[76] In 1940 and 1941, the Americans and the Chinese decided to organise a volunteer squadron of American planes and pilots to attack the Japanese from Chinese bases. Known as the Flying Tigers, the unit was commanded by Claire Lee Chennault. Its first combat came two weeks after the attack on Pearl Harbor.[77]

Taking advantage of the situation, Thailand launched the Franco-Thai War in October 1940. Japan stepped in as a mediator in the war in May 1941 and allowed its ally to occupy the bordering provinces in Cambodia and Laos. In July 1941, as Operation Barbarossa had effectively neutralised the Soviet threat, the faction of the Japanese military junta supporting the "Southern Strategy" pushed through the occupation of the rest of French Indochina.

The US reacted by seeking to bring the Japanese war effort to a complete halt by imposing a full embargo on all trade between the United States to Japan on August 18, 1941, and demanding a Japanese withdrawal of all troops from China and Indochina. Japan was dependent on the United States for 80% of its oil, which resulted in an economic and military crisis for Japan since it could not continue the war effort against China without access to petroleum and oil products.[78]

Attack on Pearl Harbor, December 1941

On 7 December 1941, without a declaration of war,[79] the Imperial Japanese Navy attacked Pearl Harbor with the aim of destroying the main American battle fleet at anchor. Meanwhile, other Japanese forces attacked the American-held Philippines and the British Empire in Malaya, Singapore, and Hong Kong. The following day, an official Japanese declaration of war on the United States and the British Empire was printed on the front page of all Japanese newspapers' evening editions.[80] International time differences caused the announcement to take place between midnight and 3 a.m. on 8 December in North America and at about 8 a.m. on 8 December in the United Kingdom.

Canada declared war on Japan on the evening of 7 December, and a royal proclamation affirmed the declaration the next day.[81] The British declared war on Japan on the morning of 8 December and specifically identified the attacks on Malaya, Singapore and Hong Kong as the cause but omitted any mention of Pearl Harbor.[82] The United States declared war upon Japan on the afternoon of 8 December, nine hours after the United Kingdom, and identified only "unprovoked acts of war against the Government and the people of the United States of America" as the cause.[83]

Four days later, the US was brought into the European war when on December 11, 1941, Nazi Germany and Fascist Italy declared war on the United States. Hitler chose to declare that the Tripartite Pact required Germany to follow Japan's declaration of war although American destroyers escorting convoys and German U-boats had been de facto at war in the Battle of the Atlantic. The declaration of war effectively ended US isolationist sentiment, and the country immediately reciprocated and so formally entered the war in Europe.[84]

## See also

[edit]

* Diplomatic history of World War II
* European Civil War
* European interwar economy
* International relations (1919–1939)
* Interwar period, worldwide
* Jewish war conspiracy theory: an antisemitic conspiracy theory promoted by the Nazis that falsely claims that the Jews had started World War II, used by the Nazis during the war to justify antisemitism, and after the war by Neo-Nazis to promote Nazism
* European foreign policy of the Chamberlain ministry
* Timeline of events preceding World War II
* Events preceding World War II in Asia
* Events preceding World War II in Europe

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### Cited sources

[edit]

* Kallis, Aristotle (2000). Fascist Ideology. London: Routledge. ISBN 9780415216128.
* Paxton, Robert O. (2011). Europe in the Twentieth Century. United States: Wadsworth. ISBN 9781133171126.

## Further reading

[edit]

* Bell, P. M. H. The Origins of the Second World War in Europe (Routledge, 2014).

* Dowswell, Paul. The Causes of World War II (Heinemann, 2002).

* Kagan Robert. The Ghost at the Feast: America and the Collapse of World Order, 1900-1941 (Knopf, 2023); excerpt

* Morewood, Steve. "The origins of World War Two in Europe." in Themes in Modern European History, 1890-1945 (Routledge, 2008) pp. 291-330.

* Overy, Richard J. The Origins of the Second World War (Routledge, 2014) . a major scholarly study
* Tarling, Nicholas, and Margaret Lamb. From Versailles to Pearl Harbor: The Origins of the Second World War in Europe and Asia (Palgrave Macmillan, 2001) online.
* Watt, Donald Cameron. How War Came: The Immediate Origins of the Second World War, 1938–1939 (1989). online a major scholarly study; online review

* Weinberg, Gerhard L. A world at arms: A global history of World War II (Cambridge University Press, 2005).

## External links

[edit]

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* Causes of WWII - World History Encyclopedia
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* The Way to Pearl Harbor: US vs Japan
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* Military equipment
* Military production
* Naval history
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* Opposition
* Technology
* Allied cooperation
* Mulberry harbour
* Total war
* Strategic bombing
* Puppet states
* Women
* Art and World War II
* Music in World War II
* Weather events during World War II

|

Theaters|

* Asia and Pacific
* China
* South-East Asia
* Pacific
* North and Central Pacific
* South-West Pacific
* Indian Ocean
* Europe
* Western Front
* Eastern Front
* Mediterranean and Middle East
* North Africa
* East Africa
* Italy
* West Africa
* Atlantic
* timeline
* Americas

Aftermath|

* Chinese Civil War
* Cold War
* Decolonization
* Division of Korea
* First Indochina War
* Expulsion of Germans
* Greek Civil War
* Indonesian National Revolution
* Keelhaul
* Marshall Plan
* Occupation of Germany
* Occupation of Japan
* Osoaviakhim
* Paperclip
* Soviet occupations
* Baltic
* Hungary
* Poland
* Romania
* Territorial changes of Germany
* Treaty on the Final Settlement with Respect to Germany
* United Nations

War crimes|

* Allied war crimes
* Soviet war crimes
* Atrocities against prisoners of war
* British war crimes
* United States war crimes
* German war crimes
* forced labour
* Wehrmacht war crimes
* The Holocaust
* Aftermath
* Response
* Nuremberg trials
* Italian war crimes
* Japanese war crimes
* Nanjing Massacre
* Unit 731
* Prosecution
* Croatian war crimes
* Genocide of Serbs
* Persecution of Jews
* Romanian war crimes
* Sexual violence
* German military brothels
* Camp brothels
* Rape during the occupation of Germany  / Japan  / Poland  / Manchuria
* Rape during the liberation of France  / Serbia
* Sook Ching
* Comfort women
* Rape of Manila
* Marocchinate

Participants|

| Allies|

* Algeria
* Australia
* Belgium
* Brazil
* Bulgaria (from September 1944)
* Canada
* China
* Cuba
* Czechoslovakia
* Denmark
* Ethiopia
* Eswatini (formerly Swaziland)
* Finland (from September 1944)
* France
* Free France
* Greece
* India
* Italy (from September 1943)
* Liberia
* Luxembourg
* Mexico
* Netherlands
* Newfoundland
* New Zealand
* Norway
* Philippines
* Poland
* Romania (from August 1944)
* Sierra Leone
* South Africa
* Southern Rhodesia
* Soviet Union
* Tuva
* United Kingdom
* British Empire
* United States
* Puerto Rico
* Yugoslavia

|

Axis|

* Albania protectorate
* Bulgaria (until September 1944)
* State of Burma
* Republic of China (Wang Jingwei)
* Independent State of Croatia
* Finland (until September 1944)
* German Reich
* Hungary
* Azad Hind
* Iraq
* Italy (until September 1943)
* Italian Social Republic
* Empire of Japan
* Manchukuo
* Mengjiang
* Philippines
* Romania (until August 1944)
* Slovak Republic
* Thailand
* Vichy France
* Guangzhouwan
* French Indochina
* French Madagascar
* Syria–Lebanon
* French North Africa
* French West Africa
* Collaboration

Neutral|

* Afghanistan
* Andorra
* Bhutan
* Ireland
* Liechtenstein
* Monaco
* Portugal
* San Marino
* Saudi Arabia
* Spain
* Sweden
* Switzerland
* Tibet
* Turkey
* Vatican City
* Yemen

Resistance|

* Albania
* Austria
* Belgium
* Bulgaria
* Czech lands
* Denmark
* Dutch East Indies
* Estonia
* Ethiopia
* France
* Germany
* Greece
* Hong Kong
* Italy
* Japan
* Jews
* Korea
* Korean Liberation Army
* Korean Volunteer Army
* Latvia
* Lithuania
* Luxembourg
* Malaya
* Netherlands
* Northeast China
* Norway
* Philippines
* Poland
* Romania
* Thailand
* Soviet Union
* Slovakia
* Western Ukraine
* Vietnam
* Quốc dân Đảng
* Viet Minh
* Yugoslavia

POWs|

* Finnish prisoners in the Soviet Union
* German prisoners
* Soviet Union
* Azerbaijan
* United States
* United Kingdom
* Italian prisoners in the Soviet Union
* Japanese prisoners
* Soviet Union
* German atrocities against Polish POWs
* Soviet prisoners
* Finland
* atrocities by Germans
* Polish prisoners in the Soviet Union
* Romanian prisoners in the Soviet Union

Timeline|

| Prelude|

* Africa
* Second Italo-Ethiopian War
* Asia
* Second Sino-Japanese War
* Battles of Khalkhin Gol
* Europe
* Remilitarisation of the Rhineland
* Anschluss
* Munich Agreement
* Occupation of Czechoslovakia
* Operation Himmler
* Italian invasion of Albania

|

1939|

* Invasion of Poland
* Battle of the Atlantic
* Phoney War
* First Battle of Changsha
* Battle of South Guangxi
* Winter War
* 1939–1940 Winter Offensive

1940|

* Norwegian campaign
* German invasion of Denmark
* Battle of Zaoyang–Yichang
* German invasion of Luxembourg
* German invasion of the Netherlands
* German invasion of Belgium
* Battle of France
* Dunkirk evacuation
* Battle of Britain
* Battle of the Mediterranean
* North Africa
* West Africa
* British Somaliland
* Hundred Regiments Offensive
* Baltic states
* Eastern Romania
* Japanese invasion of French Indochina
* Italian invasion of Greece
* Compass

1941|

* Battle of South Henan
* Battle of Shanggao
* Invasion of Yugoslavia
* German invasion of Greece
* Battle of Crete
* Anglo-Iraqi War
* Battle of South Shanxi
* Syria–Lebanon campaign
* East African campaign
* Invasion of the Soviet Union
* Summer War
* Finland (Silver Fox)
* Lithuania
* Battle of Kiev
* Anglo-Soviet invasion of Iran
* Second Battle of Changsha
* Siege of Leningrad
* Battle of Moscow
* Bombing of Gorky
* Siege of Sevastopol
* Attack on Pearl Harbor
* Japanese invasion of Thailand
* Fall of Hong Kong
* Fall of the Philippines
* Battle of Guam
* Battle of Wake Island
* Malayan campaign
* Battle of Borneo
* Japanese invasion of Burma
* Third Battle of Changsha
* Greek famine of 1941–1944

1942|

* Fall of Singapore
* Battle of the Java Sea
* St Nazaire Raid
* Battle of Christmas Island
* Battle of the Coral Sea
* Battle of Madagascar
* Zhejiang-Jiangxi campaign
* Battle of Gazala
* Battle of Dutch Harbor
* Battle of Midway
* Aleutian Islands campaign
* Kiska
* Attu
* Blue
* First Battle of El Alamein
* Battle of Stalingrad
* Kokoda Track campaign
* Rzhev
* Jubilee
* Second Battle of El Alamein
* Guadalcanal campaign
* Torch
* Chinese famine of 1942–1943

1943|

* Black May
* Tunisian campaign
* Battle of West Hubei
* Battle of Attu
* Bombing of Gorky
* Battle of Kursk
* Allied invasion of Sicily
* Smolensk
* Solomon Islands campaign
* Cottage
* Battle of the Dnieper
* Allied invasion of Italy
* Armistice of Cassibile
* Burma
* Northern Burma and Western Yunnan
* Changde
* Second Battle of Kiev
* Gilbert and Marshall Islands campaign
* Tarawa
* Makin
* Bengal famine of 1943

1944|

* Tempest
* Monte Cassino / Anzio
* Korsun–Cherkassy
* Narva
* U-Go
* Imphal
* Ichi-Go
* Kohima
* Overlord
* Neptune
* Mariana and Palau
* Bagration
* Western Ukraine
* Second Battle of Guam
* Tannenberg Line
* Warsaw Uprising
* Eastern Romania
* Liberation of Paris
* Dragoon
* Gothic Line
* Belgrade offensive
* Battle of San Marino
* Lapland
* Market Garden
* Estonia
* Crossbow
* Pointblank
* Vietnamese famine of 1944–1945
* Philippines (1944–1945)
* Leyte
* Syrmian Front
* Hungary
* Budapest
* Burma (1944–1945)
* Ardennes
* Bodenplatte
* Dutch famine of 1944–1945

1945|

* Vistula–Oder
* Battle of Manila
* Battle of Iwo Jima
* Indochina
* Vienna offensive
* Project Hula
* Western invasion of Germany
* Bratislava–Brno offensive
* Battle of Okinawa
* Second Guangxi campaign
* West Hunan
* Italy (Spring 1945)
* Battle of Berlin
* Prague offensive
* Surrender of Germany
* document
* Borneo
* Taipei
* Naval bombardment of Japan
* Manchuria
* Atomic bombings
* Debate
* South Sakhalin
* Kuril Islands
* Shumshu
* Surrender of Japan
* Potsdam Declaration
* document
* End of World War II in Asia

* World portal
* Bibliography
* Category

* v
* t
* e

Military historiography

* Military history
* List of military museums

Pre-18th century
conflicts|

* Albigensian Crusade
* Catharism debate
* Crusades
* Islamic views
* Eighty Years' War
* Origins
* Fall of Babylon
* Gallic Wars
* Late Bronze Age collapse
* Dorian invasion
* Sea Peoples
* Peloponnesian War

18th and 19th
century conflicts|

| Coalition Wars
(1792–1815)|

* French Revolution
* Causes
* War in the Vendée
* Napoleonic era
* Invasion of Russia
* Waterloo

|

* American Civil War
* Origins
* Turning point
* Franco-Prussian War
* Causes
* Paris Commune
* Great Game
* Indian Rebellion of 1857
* Causes
* Paraguayan War
* War of 1812
* Origins
* War of the Pacific
* Causes

World War I|

* Causes (Color books / Fischer thesis)
* Late Ottoman genocides (Causes of the Armenian genocide)
* Patriotic consent
* Persian famine of 1917–1919
* Powder keg of Europe
* Schlieffen Plan
* Spirit of 1914 / 1917
* Treaty of Brest-Litovsk, Germany imposed this on Russia in 1918

| Treaty of
Versailles|

* Reparations
* War guilt question
* Article 231
* Reichstag inquiry

|

Interwar period|

* Burning of Smyrna
* Polish–Soviet War
* Causes
* Spanish Civil War
* Background

World War II|

* Causes
* "Blitzkrieg" concept
* Broad vs. narrow front
* German resistance to Nazism
* Nazi foreign policy debate

| Eastern Front|

* Molotov–Ribbentrop Pact
* Soviet offensive plans
* Soviets and the Warsaw Uprising
* Massacres of Poles in Volhynia and Eastern Galicia
* Winter War
* Background
* Spirit

|

The Holocaust|

* Auschwitz bombing debate
* Awareness in Nazi Germany and German-occupied Europe
* Functionalism–intentionalism debate
* In relation to the Armenian genocide / Nakba
* Pope Pius XII and the Holocaust
* Pius Wars
* "Polish death camp"
* Responsibility
* Slovakia
* Uniqueness

Pacific War|

* Atomic bombings of Hiroshima and Nagasaki
* "Battle for Australia"
* Bengal famine
* Second Sino-Japanese War
* Nanjing Massacre

Western Front|

* Battle of France
* Guilty Men
* Résistancialisme
* Vichy France

Cold War|

* Origins
* 1948 Palestine war
* Palestinian expulsion and flight / Ongoing Nakba
* Zionism as settler colonialism
* New Historians
* Malayan Emergency
* Causes
* Algerian War
* Six-Day War
* Origins
* Iranian revolution
* Causes
* Iran–Iraq War
* Falklands War
* Sovereignty dispute
* Sri Lankan civil war
* Origins

Post-Cold War|

* Russo-Georgian War
* Background
* Responsibility
* Syrian revolution
* Causes

Related|

* Conflict thesis
* Gunpowder and gun transmission
* War and genocide

* Category

* v
* t
* e

Paris Peace Conference (1919–1920)

League of Nations|

* Covenant of the League of Nations
* Members
* Organisation
* Minority Treaties
* Little Treaty of Versailles
* Mandates

Treaty of Versailles|

* "War guilt" clause
* Reparations
* Reparation Commission
* Dawes Plan
* The Hague conference on reparations
* Young Plan
* Lausanne Conference
* Locarno
* Stresa Front
* Possible cause of the Second World War
* First International Opium Convention (The Hague)

Subsequent treaties|

* Treaty of Saint-Germain-en-Laye
* Treaty of Neuilly-sur-Seine
* Treaty of Trianon

Treaty of Sèvres|

* Partition of the Ottoman Empire
* Conference of London (1920)
* San Remo conference
* Turkish National Movement
* Turkish War of Independence
* Treaty of Lausanne

Other|

* Big Four
* American Commission to Negotiate Peace
* Commission of Responsibilities
* The Inquiry
* List of participants

Paintings|

* A Peace Conference at the Quai d'Orsay
* The Signing of Peace in the Hall of Mirrors
* To the Unknown British Soldier in France

Authority control databases

National|

* United States
* Israel

Other|

* Yale LUX

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