While American national security policy has grown more interventionist since the Cold War, Washington has also hoped to shape the world on the cheap. Misled by the stunning success against Iraq in 1991, administrations of both parties have pursued ambitious aims with limited force, committing the country's military frequently yet often hesitantly, with inconsistent justification. These ventures have produced strategic confusion, unplanned entanglements, and indecisive results. This collection of essays by Richard K. Betts, a leading international politics scholar, investigates the use of...