At this time two decades ago, President George W. Bush resolved to invade Iraq and topple its brutal dictator Saddam Hussein. His decision was the most consequential American foreign policy decision since the end of the Cold War, and arguably the most significant foreign policy action of the United States in the twenty-first century. As the invasion turned into a bloody occupation and triggered civil strife and insurrection, more than two hundred thousand Iraqis perished and almost nine million were displaced or fled abroad — about one-third of Iraq’s prewar population. Two decades later, a small contingent of American troops remain in the country helping to provide security for a struggling young democracy, whose constitution, elections, parties, and political institutions, at least in part, still bear the imprint of the American occupation policies.