Freedom to express one's views is both a basic human right and a bedrock principle of democracy. If people are denied the right to speak their minds, something essential to their sense of autonomy is removed. Democracy cannot function without opponents being able to criticize the actions of those in power. Elections are meaningless charades if those challenging the government are muzzled.

Freedom of expression took a long time to develop. Governments everywhere and at all times usually prefer to hear praise rather than criticism. In the past, most governments were unable or unwilling to separate disagreement with their policies from outright disloyalty. While critics were sometimes tolerated, governments were loathe to recognize freedom of expression as a right. In Western civilization, seventeenth-century England primarily was where the idea of a "loyal opposition" first began to take hold.

Though the concept is now widespread...