America values dissent. It tolerates, encourages, and protects it. But what is this thing we value? That is a question never asked. "Dissent" is treated as a known fact. For all that has been said about dissent - in books, articles, judicial opinions, and popular culture - it is remarkable that no one has devoted much, if any, ink to explaining what dissent is. No one has attempted to sketch its philosophical, linguistic, legal, or cultural meanings...