Dick Cheney and Colin Powell emerged on the national scene more than 30 years ago, and it is easy to forget that they were once allies. It was Cheney who pressed for Powell's appointment as chairman of the Joint Chiefs of Staff, over the initial skepticism of the White House. And the two men collaborated closely in the successful American wars in Panama and Iraq during the George H. W. Bush administration.

But from that pinnacle, conflicts of ideology and sensibility drove Cheney and Powell apart. Under George W. Bush, they fell into ever-deepening conflict. Cheney personified the idea that America should use its unrivaled power to reorder the world, using military force and ignoring objections from its longstanding allies. Powell believed that the United States should operate through diplomacy as much as possible, relying on the alliances it had forged.

In this wide-ranging and deeply researched reassessment of these two major figures, James Mann explores each man's biography and philosophical predispositions to show how and why this deep and permanent rupture occurred. Through dozens of original interviews and surprising revelations from presidential archives, he brings to life the very human story of how this influential friendship turned so sour and how their enmity colored the way America acts in the world.