Soon after it first appeared in The Mysterious Stranger: A Romance (1916), the phrase “against the assault of laughter nothing can stand” became one of the most popular quotes from the work of Mark Twain. The present article draws attention to the complications that arise in the endeavor to examine the substance of a catch phrase that has enjoyed widespread popularity. To explore this issue, the article places Twain's phrase in the context in which it emerged. Drawing on examples of political humor from different phases of American literary and cultural history, the article then goes on to explore the implications of imagining humor and laughter as a subversive force. By supplementing this material with a brief survey of empirical research on the effects of humor and laughter, the article ultimately challenges the contention that humor and laughter might function as a corrective force in American culture.