In its classic form, a “decisive” pitched battle was a beautifully contained event, lasting a single day, killing only combatants, and resolving legal questions of immense significance. Yet since the mid-nineteenth century, pitched battles no longer decide wars, which now routinely degenerate into general devastation. Why did pitched battle ever work as a conflict resolution device? Why has it ceased working since 1860? James Q. Whitman is Ford Foundation Professor of Comparative and Foreign Law, Yale Law School. This Maurice and Muriel Fulton Lecture in Legal History was recorded May 7, 2009. Less