Demosthenes, the Athenian rhetorician and champion of liberty, pointed out around 355 B.C. that residents of Athens were free to praise Sparta's regime, but Spartans were banned from praising Athens. In 1689, the British passed a law guaranteeing freedom of speech in Parliament. A century later, French revolutionaries incorporated into law the Declaration of the Rights of Man, which established free speech as a universal right. Two years later, the Americans ratified the First Amendment, which guarantees that the state shall not infringe on the right to free speech. Roughly a century and half later, in 1948, the United Nations...