White House is seen in Washington.

his paper focuses on how Congress and the American people evaluate presidential wars of choice. When it comes to whether or not to use American military power, presidential discretion is virtually unchecked1. The war power is for that reason the issue that best exposes the costs of a too exclusive reliance on retrospective as opposed to prospective accountability. I use brief case studies of Korea, Vietnam and Iraq to show that reliance on retrospective accountability is particularly unsatisfactory in the context of peace and war. In the runup to each of these wars, for example, Congress deferred to presidents who insisted on the need for military action (or authorization for such action) despite lack of clear provocation (e.g., an attack on the United States) and without a vision of the objective backed by well-specified operational plans that could stand the test of time. In each of these cases, Congress offered little serious oversight until stirred to do so by shifts in public opinion brought on by mounting costs in American blood, treasure, international credibility and domestic harmony not justified by battlefield success. Public opinion was a force to be reckoned with, as shown by its eventual impact on Congress and on the subsequent political fortunes of presidents Truman, Johnson and the second Bush. But citizens did not press Congress to act until it was too late to influence the initial decisions to send in the troops