In Brandenburg v. Ohio, the Supreme Court held that abstract advocacy of lawlessness and violence is protected speech under the First Amendment. Even in a society based on laws, people should be free to express disagreement with the law and call on others to break the law (inflammatory speech).
I think that’s generally acceptable and fair. If someone believes that smoking dope shouldn’t be a crime, and carefully describes to his or her readers how to cultivate and use the drug, then he or she should be permitted to do so. The crime is drug use, not the description of or incitement to use drugs. The same is true for a more extreme example, such as the infamous book called “The Hit Man Manual” (see the Rice v. Paladin Enterprises case). Also, we don’t want to ban chemistry books because someone may use them to build a bomb.
However, it is equally acceptable, also according to Brandenburg v. Ohio, that speech which incites imminent, illegal conduct may itself be made illegal:
The constitutional guarantees of free speech and free press do not permit a State to forbid or proscribe advocacy of the use of force or of law violation except where such advocacy is directed to inciting or producing imminent lawless action and is likely to incite or produce such action. Brandenburg v. Ohio
If speech intends to produce illegal actions, and if, as a result of this speech, the illegal actions are imminent and likely, then there is a reason to limit freedom of speech. In the words of Justice Black (who was, by the way, something of a first amendment absolutist):
It rarely has been suggested that the constitutional freedom for speech and press extends its immunity to speech or writing used as an integral part of conduct in violation of a valid criminal statute. We reject the contention now.
When speech acts contribute substantively to criminal acts, the speech acts are considered to be “aiding and abetting”. The fact that “aiding and abetting” of an illegal act may be carried out through speech is no bar to its illegality. (source)
The justifications for free speech that apply to speakers do not reach communications that are simply means to get a crime successfully committed. K. Greenawalt in “Speech, Crime, and the Uses of Language”
Aiding and abetting a crime can be criminal in itself, even if it takes the form of the spoken or written word. The First Amendment doesn’t provide immunity from prosecution because someone uses speech or the printed word in encouraging and counseling others in the commission of a crime.
Volokh has given the following example:
A Virginia woman has been arrested for blogging about the members of a local drug task force. The charge is harassment of a police officer. She apparently posted on the blog one officer’s home address, as well as photos of all members of the task force, and a photo of one officer getting into his unmarked car in front of his home….
Photographing, writing about, and criticizing police officers, even by name, should of course be legal. But it’s a tougher call when the officers in question work undercover. Naming them, posting their photos, posting their addresses, are all pretty clearly efforts to intimidate them, and it isn’t difficult to see how doing so not only makes it more difficult for them to do their jobs, but may well endanger their lives….
When may speech be restricted because it provides others with information that may help them commit crimes? Here, the information may help people kill police officers, or at least conceal their crimes from police officers (once the undercover officers’ covers are blown). (source)
However, this doesn’t mean that all inflammatory speech or every publication and distribution of instructions on how to act illegally, can be suppressed and made illegal. The “Brandenbrug test” has to be successful first, which means that there has to be more than mere intent. There has to be incitement of an imminent lawless act, as well as the likelihood that this incitement produces or helps to produce such an act.