Prior restraint is a legal term referring to the prevention or restriction of speech prior to publication. Prior restraint is nearly always found to be unconstitutional, as it violates the First Amendment rights of freedom of speech and freedom of the press.
The leading precedents against prior restraints are:
An exceptional case that allowed a prior restraint was USA v The Progressive. It delayed publication of a magazine article on H-bomb secrets for six months in 1979.
As the Supreme Court of Kentucky summarized, equity does not support a prior restraint:
Aside from the First Amendment's heavy presumption against prior restraints, courts have long held that equity will not enjoin a libel. See Nebraska Press Ass'n, 427 U.S. at 589; Kramer v. Thompson, 947 F.2d 666, 677-78 (3rd Cir. 1991); Community for Creative Non-Violence v. Pierce, 814 F.2d 663, 672, 259 U.S. App. D.C. 134 (D.C. Cir. 1987) ("The usual rule is that equity does not enjoin a libel or slander and that the only remedy for defamation is an action for damages."); American Malting Co. v. Keitel, 209 F. 351, 354 (2d Cir. 1913) ("Equity will not restrain by injunction the threatened publication of a libel, as such, however great the injury to property may be. This is the universal rule in the United States . . . ."); Metropolitan Opera Assn, Inc. v. Local 100, Hotel Employees and Restaurant Employees International Union, 239 F.3d 172, 177 (2d Cir. 2001); 42 Am. Jur. 2d, Injunctions, ยง 97 (2010) ("The general rule is that equity does not enjoin libel, rather, the only remedy for defamation is an action for damages, and there is a heavy presumption that prior restraints on expression are unconstitutional."). (footnotes omitted)
Hill v. Petrotech Res. Corp., 325 S.W.3d 302, 306 (Ky. 2010).