"Now, shut up! Shut up, all of you! Listen to me, you hicks. Yeah, you're hicks too, and they fooled you a thousand times like they fooled me. But this time, I'm going to fool somebody. I'm going to stay in this race. I'm on my own and I'm out for blood.
--Willlie Stark (All the King's Men)
Judge Nap discusses the law surrounding political speech in light of recent disruptions and violence at campaign events of Donald Trump. In 1946 a Catholic priest named Arthur Terminiello gave an incendiary speech against communism and what he thought was President Truman's comfort with it. The speech was given in a Chicago hall that his supporters had rented.
Although the hall capacity was about 800 people, about 3x that many showed up for the event, with most of the overflow being opposed to the speech. The priest's speech enraged his detractors to the point where Chicago police asked him to stop speaking and leave the building.
The priest refused. Ultimately push came to shove and protesters rushed the stage and attempted to attack the speaker. The police escorted Terminiello out of the building and then arrested him for inciting a riot. None of the rioters who destroyed property and attacked the priest were arrested.
The priest was tried and convicted, but the case was ultimately overturned by the U.S. Supreme Court which essentially saved the First Amendment from authoritarian impulses to suppress speech that some might find uncomfortable. The court warned that police cannot sit idly by and permit protesters to silence speakers using what legally is known as a 'heckler's veto'. The police have an affirmative obligation to protect the speaker's right to speak and the audience's right to hear.
When a speech takes place in a public place, then the protester's right to peacefully protest must also be upheld. When meetings take place on private grounds, as Jacob Hornberger observes, then protesters do not maintain most of those rights. Under the principles of private property, owners of the property and event can run political rallies how they want and have the right to physically remove those who disrupt the event.
What about allegations that Donald Trump himself is responsible for the violence that has erupted at his rallies? According to the Judge, if Trump publicly calls for violence and there is no time or ability for any speech to neutralize his demand and the demanded violence takes place, then Trump's speech is unprotected and he can be prosecuted for inciting a riot. If there is time for more speech to counsel against violence--even if no neutralizing speech is actually uttered, then Trump cannot be prosecuted. Before any prosecution for political speech commences, the court must eliminate any possible lawful interpretation of the speaker's words.
Stated differently, the rule is that all innocuous speech is protected, and all speech is innocuous when there is time for more speech to rebut or neutralize it.
I would also think that if it can be shown that protestors attended a campaign rally with intentions of disrupting the event, then they are liable.
The purpose of the First Amendment is to recognize and protect the natural human right to form and express thought, regardless of whom it might offend. It encourages wide open challenging speech about government that requires no permission slip.