Is there a First Amendment right to intimidate people?
What is intimidation?
I don’t see easy answers to these questions, because to a certain extent, demonstrations — and demonstrators — are intended to intimidate. (I have experienced this personally on a number of occasions, and I won’t bore readers by quoting yet again from numerous posts.)
Not only do demonstrators fully intend to intimidate their targets, but their goal is to discourage people from sympathizing with their targets. If the target is popular (or sympathetic), the goal is to make him unpopular (and unsympathetic). And if the target is unpopular or unsympathetic, the goal is to send a message along the lines of “Don’t even think of sympathizing with this scum!” Open mindedness becomes a casualty. In the name of “free speech” of course.
Whether demonstrations constitute intimidation in the legal sense is another issue. The standard legal definition provides no clear line:

INTIMIDATE – means to intentionally say or do something which would cause a person of ordinary sensibilities to be fearful of bodily harm. It is not necessary to prove that the victim was actually frightened, and neither is it necessary to prove that the behavior of the person was so violent that it was likely to cause terror, panic or hysteria.

A concerned old lady holding a sign would certainly not constitute intimidation, because a “person of ordinary sensibilities” would not fear bodily harm. But a huge angry crowd, hurling insults and shouting obscene slogans, that very well might be. The larger the crowd, the more intimidating it is. Intimidation can be accomplished by sheer numbers alone. But then, even a smaller crowd of demonstrators can be extremely intimidating, especially if they are known for a history of violence. Angry large tattooed bearded men holding signs saying “TEAMSTERS LOCAL 666 — DO NOT CROSS OUR LINE!” would frighten most people away. Why? Because they would have a reasonable fear of bodily harm.
Where this gets especially dicey is in the case of demonstrators targeting people who have to be at a certain place — i.e. a captive target group. If you have to go to work, and the Teamsters are there in force, they have their First Amendment rights, but what about your right to earn a livelihood? And what if the demonstrators target your home? Even if that’s done in a “peaceful” manner, it’s enough to make most people give way to whatever the demands are. So I would call it intimidation.
What about jurors? While there are strict laws prohibiting “jury intimidation,” these laws typically contemplate criminals, mob cronies trying to frighten individual jurors. Where it comes to demonstrators, it’s a fuzzy area.
Not so fuzzy, though, to have escaped the attention of the Village Voice’s Nat Hentoff. Writing about the trial of a police officer in the Abner Louima shooting case, he describes the scene:

And when this federal jury declared itself seriously divided, Reverend Al, in a televised weekend press conference, urged his supporters to insist that Schwarz [the accused cop] be thoroughly convicted. Accordingly, on the following Monday, while the jury continued to deliberate, busloads of anti-Schwarz demonstrators descended on the courthouse, shouting dire epithets and becoming so boisterous that Schwarz and his attorney, Ronald Fischetti, needed a police escort to get through. The intent was to convince the jury to do the right thing. Remember: This jury was not sequestered.

If that’s not intimidation, then what is?
Remember, these jurors are not like military recruits trained and hardened in boot camp. They are ordinary people, who have to ride the subway home, and they know that what they are doing is a matter of public record, and that thuggish activists will remember whatever they do long after the case has faded away into oblivion. How many people remember Abner Louima today? Two groups: political junkies and angry activists. Political junkies won’t hurt you, but it’s in the nature of activists to always be angry, and never forget.
The thing is, our legal system requires that these cases be tried, and juries have to hear them. But who in the hell would want want to be a juror in a high-profile case that attracts the presence of demonstrators? This is not to say that demonstrators are necessarily wrong (in some cases I would agree with their position), but I do think their very presence has an intimidating on those inclined to be fair and impartial.
These are just a few examples. I can’t draw the exact line, but I think there is real tension between the First Amendment and the right to be free from intimidation.
Maybe I should have titled this post “Why Activists Win, Part IV”