Harry Truman's administration began searching for an American response to the clash in Indochina between French colonialism and Vietminh communism in 1945. 30 years and five administrations later, Gerald Ford and his aides tried unsuccessfully to solicit additional aid for South Vietnam from a reluctant Congress. For Truman, Ford and every American leader in between, the dilemma in Vietnam hung ominously over the presidency. In ''Shadow on the White House'', seven historians examine how the leadership of six presidents and an issue that grew into a difficult and often unpopular war shaped each other. Focusing on the personalities, politics, priorities and actions of the presidents as they confronted Vietnam, the authors consider the expansion of presidential power in foreign-policy formulation since World War II. In their analyses, they chronicle the history of executive leadership as it related to Vietnam, assess the presidential prerogatives and motives on war and peace issues, and clarify the interconnection between the modern presidency and the nation's frustrating and humiliating failure in Southeast Asia. Although other histories have been written about the Vietnam experience, this book is a systematic and comparative survey on presidential leadership as it relates to the war issue. It is organised by presidential administrations, giving a detailed examination of each president's decisions and policies. Based on the most recently opened archival sources, the essays provide a framework on which to hang the events of the war.