Despite the fact that Americans pride themselves on constitutional protections for free speech, there have been many attempts to limit speech in the United States. Beginning in 1789 with the First Sedition Act, Congress has passed laws banning diverse kinds of speech: criticism of the government, speaking out against war, associating with the Communist party, obscenity, slander, libel, "fighting words," and seditious speech that attempts to overthrow the government. None of these limits have been so controversial or so damaging as the attempt by Senator Joseph McCarthy in the 1950s to purge the United States of anyone remotely connected with the Communist party. His unsubstantiated charges led to wrecked lives and careers in all walks of life. The inherent irony of McCarthyism—the name given to the attempts to seek out and criminalize those suspected of sympathizing with communism—was that by the time of his "Red Scare," American...