Mr. Justice Harlan delivered the opinion of the Court.

These 14 petitioners stand convicted, after a jury trial in the United States District Court for the Southern District of California, upon a single count indictment charging them with conspiring (1) to advocate and teach the duty and necessity of overthrowing the Government of the United States by force and violence, and (2) to organize, as the Communist Party of the United States, a society of persons who so advocate and teach, all with the intent of causing the overthrow of the Government by force and violence as speedily as circumstances would permit [in violation of the Smith Act, see below.]....

In the view we take of this case, it is necessary for us to consider only the following of petitioners' contentions: ... (2) that the trial court's instructions to the jury erroneously excluded from the case the issue of "incitement to action"; (3) that the evidence was so insufficient as to require this Court to direct the acquittal of these petitioners.... For reasons given hereafter, we conclude that these convictions must be reversed and the case remanded to the District Court with instructions to enter judgments of acquittal as to certain of the petitioners, and to grant a new trial as to the rest.

Petitioners contend that the instructions to the jury were fatally defective in that the trial court refused to charge that, in order to convict, the jury must find that the advocacy which the defendants conspired to promote was of a kind calculated to "incite" persons to action for the forcible overthrow of the Government. It is argued that advocacy of forcible overthrow as mere abstract doctrine is within the free speech protection of the First Amendment; that the Smith Act, consistently with that constitutional provision, must be taken as proscribing only the sort of advocacy which incites to illegal action; and that the trial court's charge, by permitting conviction for mere advocacy, unrelated to its tendency to produce forcible action, resulted in an unconstitutional application of the Smith Act. The Government, which at the trial also requested the court to charge in terms of "incitement," now takes the position, however, that the true constitutional dividing line is not between inciting and abstract advocacy of forcible overthrow, but rather between advocacy as such, irrespective of its inciting qualities, and the mere discussion or exposition of violent overthrow as an abstract theory.

We are thus faced with the question whether the Smith Act prohibits advocacy and teaching of forcible overthrow as an abstract principle, divorced from any effort to instigate action to that end, so long as such advocacy or teaching is engaged in with evil intent. We hold that it does not.

The distinction between advocacy of abstract doctrine and advocacy directed at promoting unlawful action is one that has been consistently recognized in the opinions of this Court. This distinction was heavily underscored in Gitlow v. New York, in which the statute involved was nearly identical with the one now before us, and where the Court, despite the narrow view there taken of the First Amendment, said:

The statute does not penalize the utterance or publication of abstract "doctrine" or academic discussion having no quality of incitement to any concrete action.... It is not the abstract "doctrine" of overthrowing organized government by unlawful means which is denounced by the statute, but the advocacy of action for the accomplishment of that purpose....

What we find lacking in the instructions here is illustrated by contrasting them with the instructions given to the Dennis jury, upon which this Court's sustaining of the convictions in that case was bottomed. There the trial court charged:

In further construction and interpretation of the statute [the Smith Act] I charge you that it is not the abstract doctrine of overthrowing or destroying organized government by unlawful means which is denounced by this law, but the teaching and advocacy of faction for the accomplishment of that purpose, by language reasonably and ordinarily calculated to incite persons to such action. (Emphasis added.)

We recognize that distinctions between advocacy or teaching of abstract doctrines, with evil intent, and that which is directed to stirring people to action, are often subtle and difficult to grasp, for in a broad sense, as Mr. Justice Holmes said in his dissenting opinion in Gitlow, "Every idea is an incitement.'' But the very subtlety of these distinctions required the most clear and explicit instructions with reference to them, for they concerned an issue which went to the very heart of the charges against these petitioners. The need for precise and understandable instructions on this issue is further emphasized by the equivocal character of the evidence in this record.... Instances of speech that could be considered to amount to "advocacy of action" are so few and far between as to be almost completely overshadowed by the hundreds of instances in the record in which overthrow, if mentioned at all, occurs in the course of doctrinal disputation so remote from action as to be almost wholly lacking in probative value. Vague references to "revolutionary" or "militant" action of an unspecified character, which are found in the evidence, might in addition be given too great weight by the jury in the absence of more precise instructions. Particularly in light of this record, we must regard the trial court's charge in this respect as furnishing wholly inadequate guidance to the jury on this central point in the case. We cannot allow a conviction to stand on such "an equivocal direction to the jury on such a basic issue."

... As to the petitioners Connelly, Kusnitz, Richmond, Spector, and Steinberg we find no adequate evidence in the record which would permit a jury to find that they were members of such a conspiracy ]to advocate the violent or unlawful overthrow of the government]. For all purposes relevant here, the sole evidence as to them was that they had long been members, officers, or functionaries of the Communist Party of California; and that standing alone, as Congress has enacted in Section 4(f) of the Internal Security Act of 1950, makes out no case against them....

... We therefore think that as to these petitioners the evidence was entirely too meagre to justify putting them to a new trial, and that their acquittal should be ordered.

As to the nine remaining petitioners, we consider that a different conclusion should be reached.... In short, while the record contains evidence of little more than a general program of educational activity by the Communist Party which included advocacy of violence as a theoretical matter, we are not prepared to say, at this stage of the case, that it would be impossible for a jury, resolving all conflicts in favor of the Government and giving the evidence as to these San Francisco and Los Angeles episodes its utmost sweep, to find that advocacy of action was also engaged in when the group involved was thought particularly trustworthy, dedicated, and suited for violent tasks.
 

Mr. Justice Black concurring and dissenting.

I would reverse every one of these convictions and direct that all the defendants be acquitted. In my judgment the statutory provisions on which these prosecutions are based abridge freedom of speech, press, and assembly in violation of the First Amendment to the United States Constitution.

In essence, petitioners were tried upon the charge that they believe in and want to foist upon this country a different and to us a despicable form of authoritarian government in which voices criticizing the existing order are summarily silenced. I fear that the present type of prosecutions are more in line with the philosophy of authoritarian government than with that expressed by our First Amendment.

Doubtlessly, dictators have to stamp out causes and beliefs which they deem subversive to their evil regimes. But governmental suppression of causes and beliefs seems to me to be the very antithesis of what our Constitution stands for. The choice expressed in the First Amendment in favor of free expression was made against a turbulent background by men such as Jefferson, Madison, and Mason--men who believed that loyalty to the provisions of this Amendment was the best way to assure a long life for this new nation and its Government. Unless there is complete freedom for expression of all ideas, whether we like them or not, concerning the way government should be run and who shall run it, I doubt if any views in the long run can be secured against the censor. The First Amendment provides the only kind of security system that can preserve a free government-one that leaves the way wide open for people to favor, discuss, advocate, or incite causes and doctrines however obnoxious and antagonistic such views may be to the rest of us.