Part III, which begins in January 1965 and ends in January 1967, treats the watershed period of U.S. involvement in the war, from President Johnson's decision to bomb North Vietnam and to send U.S. ground forces into South Vietnam, through the buildup of military forces and political cadres required by the new U.S. role in the war. This volume examines Johnson's policymaking, his interaction with military advisors and with Congressional critics such as Mike Mansfield, and his reactions as protests against the war began to grow.