In 1948, eleven Communist Party leaders were convicted of advocating the violent overthrow of the US government and for the violation of several points of the Smith Act.

The party members who had been petitioning for socialist reforms claimed that the act violated their First Amendment rights to freedom of speech and that they served no clear and present danger to the nation.

[12] The defense employed a three-pronged strategy: First, portraying the CPUSA as a conventional political party, which promoted socialism by peaceful means; second, employing the "labor defense" tactic to attack the trial as a capitalist venture which could never provide a fair outcome to proletarian defendants; and third, using the trial as an opportunity to publicize CPUSA policies.

Several times in July and August, the judge held defense attorneys in contempt of court, and told them their punishment would be meted out upon conclusion of the trial.

Dennis had been convicted of conspiring and organizing for the overthrow and destruction of the United States government by force and violence under provisions of the Smith Act.

In affirming the conviction, a plurality of the Court adopted Judge Learned Hand's formulation of the clear and probable danger test, an adaptation of the clear and present danger test: In each case [courts] must ask whether the gravity of the "evil", discounted by its improbability, justifies such invasion of free speech as necessary to avoid the danger.In his dissent, Black wrote: These petitioners were not charged with an attempt to overthrow the Government.

The charge was that they agreed to assemble and to talk and publish certain ideas at a later date: The indictment is that they conspired to organize the Communist Party and to use speech or newspapers and other publications in the future to teach and advocate the forcible overthrow of the Government.

So long as this Court exercises the power of judicial review of legislation, I cannot agree that the First Amendment permits us to sustain laws suppressing freedom of speech and press on the basis of Congress' or our own notions of mere "reasonableness."

There is hope, however, that in calmer times, when present pressures, passions and fears subside, this or some later Court will restore the First Amendment liberties to the high preferred place where they belong in a free society.

In 1957, the Court in Yates v. United States restricted the holding in Dennis, ruling that the Smith Act did not prohibit advocacy of forcible overthrow of the government as an abstract doctrine.

Brandenburg was a de facto overruling of Dennis, defining the bar for constitutionally unprotected speech to be incitement to "imminent lawless action".