'These people'. How convenient. In any large group there will be a violent type - so we'll take the actions of a few individuals, claim guilt by association against anyone that shares some of the same views, and presto, we can exercise prior restraint against free speech and free assembly, anytime and anywhere it's convenient.
Sure they have blac bloc. And they'll cite Tim McVeigh. Bank on it. As a matter of fact, the left holds that FReepers especially are among the most violent elements of the right. Sure its not true, but when they take office again, it won't matter. You'll have set (yet another of) Clintons policies in cement, and forfeited any credibility on the issue.
And so a loop whole in the First Amendment large enough to drive a truck (or a motorcade) through is created. If a tree falls in the forest and no one hears it, it doesn't matter if the tree fell at all. The same theory is held by these ENEMIES OF FREE SPEECH as they restrict protesters (but not supporters mind you) to free speech zones where no one will see or hear them.
Law and order: it's what we believe in.
Bologna. Here's a law that is ingnored when convenient by 'conservatives':
Amendment I
Congress shall make no law...abridging the freedom of speech, ...or the right of the people peaceably to assemble.