This is a story of ever-expanding presidential powers in an age of unwinnable wars. Harry Truman and Korea, Lyndon Johnson and Vietnam, George W. Bush and Iraq: three presidents, three ever broader interpretations of the commander in chief clause of the Constitution, three unwinnable wars, and three presidential secrets. Award-winning presidential biographer and military historian Geoffrey Perret places these men and events in the larger context of the post-World War II world to establish their collective legacy: a presidency so powerful it undermines the checks and balances built into the Constitution, thereby creating a permanent threat to the Constitution itself. In choosing to fight in Korea, Vietnam, and Iraq, Truman, Johnson, and Bush alike took counsel of their fears, ignored the advice of the professional military and major allies, and were influenced by facts kept from public view. Convinced that an ever-more powerful commander in chief was the key to victory, they misread the moment. Since World War II wars have become tests of stamina rather than strength, and more likely than not they sow the seeds of future wars. Yet recent American presidents have chosen to place their country in the forefront of fighting them. In the course of doing so, however, they gave away the secret of American power--for all its might, the United States can be defeated by chaos and anarchy.