If the government does not protect our freedom of speech by force, America will join Europe’s climate of self-censorship. Europeans are all too well acquainted with the fear of criticizing Islam. To cite just a few of depressingly many examples: a painter, Rashid Ben Ali, is forced into hiding after one of his shows “featured satirical work critical of Islamic militant’s violence”; a politician, Ayaan Hirsi Ali, must go underground after it becomes known that she has renounced her Islamic faith; and a film director, Theo van Gogh, is savagely stabbed to death for making a film critical of Islamic...