As the fifteenth anniversary of the Iraq war approaches, a debate has arisen over the war’s intellectual origins. G. John Ikenberry and Dan Deudney argue that it was predominantly a realist war, not a liberal one. I demonstrate, however, that both liberals and liberalism were deeply implicated in the decision to strike Iraq, and the wider public case for doing so. Liberal ideas were not a retrospective face-saving fiction after the invaders discovered Saddam had no WMD arsenal. Rather, ambitious objectives for regional transformation were central to the drive for war from the beginning. Liberalism married with the capabilities of a superpower gives America a proclivity for reckless military adventures. So long as liberalism, untempered by prudential balance-of-power realism, remains a central engine of American grand strategy, the USA will be prone to further such tragedies.