We must preserve the right of free speech and the right of free assembly. But the right of free speech does not carry with it, as has been said, the right to holler fire in a crowded theater. We must preserve the right to free assembly, but free assembly does not carry with it the right to block public thoroughfares to traffic. We do have a right to protest, and a right to march under conditions that do not infringe the constitutional rights of our neighbors. And I intend to protect all those rights as long as I am permitted to serve in this office. We will guard against violence, knowing it strikes from our hands the very weapons which we seek—progress, obedience to law, and belief in American values.

The American Promise (1965)