I think sedition was always protected under the Constitution, and was vehemently opposed by many Founding Fathers, in particular the main author of the Constitution James Madison and the author of the Declaration of Independence Thomas Jefferson. As an example, the Alien and Sedition Acts of 1798 were never struck down by a Supreme Court because the principle of judicial review did not exist yet, but were violently opposed by Jefferson and Madison, with Jefferson even suggesting that Kentucky secede in protest of the legislation.
However, purposive interpretation or doctrinalism might suggest otherwise. The Espionage Act of 1918 and the Smith Act of 1940 were never struck down in Court, and prosecution of speech that was harmful to the government was tacitly accepted.
I, for one, am a First Amendment absolutist. Once we begin cracking down on speech that ISIS, we have set the precedent that it is constitutional to deny first amendment rights to enemies of the state.
This is dangerous.
The Founding Fathers feared above all tyrannical governments. I share this fear, at least theoretically.
It is not hard to imagine a scenario in which the government, perhaps influenced by desire for power, despotism, or the clamoring of the majority, choose to designate American citizens enemies of the government and thus abridge their constitutional rights. Indeed this has already happened (see the case of Anwar al-Alwaki, and others).
From there, it is only a little harder to imagine a government, motivated by the same urges, designates American citizens fighting for righteous causes enemies of the state, and thus abridge constitutional rights. For example, those fighting for firearm rights under the Second Amendment or civil rights under the Fourteenth Amendment might be seen as enemies of the state, and thus denied First Amendment, or more dangerously, Fourth, Fifth, Sixth, Seventh, and Eighth Amendment rights.
With this specter looming, I choose constitutional absolutism. We must fight against the infringement on our rights at all costs. Too many despots have used “enemies of the state” or “security” as excuses to gain the acquiescence of their citizenry to repression. We must remain vigilant, so that this cannot let that happen in our country.
That said, I’d like to make clear that I do not believe there exist any vile villains vigorously vanguarding vigorous violations of volition in government. I don’t see anyone plotting any of these moves. But it is better to remain uncompromising now, so if later the threat materializes, we are ready with precedent and custom to fight it.