Jay Near published a scandal sheet in Minneapolis, in which he attacked local officials, charging that they were implicated with gangsters. Minnesota officials obtained an injunction to prevent Near from publishing his newspaper under a state law that allowed such action against periodicals. The law provided that any person "engaged in the business" of regularly publishing or circulating an "obscene, lewd, and lascivious" or a "malicious, scandalous and defamatory" newspaper or periodical was guilty of a nuisance, and could be enjoined (stopped) from further committing or maintaining the nuisance.

Does the Minnesota "gag law" violate the free press provision of the First Amendment?

The Supreme Court held that the statute authorizing the injunction was unconstitutional as applied. History had shown that the protection against previous restraints was at the heart of the First Amendment. The Court held that the statutory scheme constituted a prior restraint and hence was invalid under the First Amendment. Thus the Court established as a constitutional principle the doctrine that, with some narrow exceptions, the government could not censor or otherwise prohibit a publication in advance, even though the communication might be punishable after publication in a criminal or other proceeding.

Source

• http://www.oyez.org/cases/1901-1939/1929/1929_91/#sort=ideology