In what significant way did President Johnson depart from the foreign policy of his predecessors regarding Vietnam?

President Johnson's decision to use U.S. troops in a combat role in Vietnam marked a notable departure from the foreign policy of his predecessors, particularly regarding the United States' involvement in Southeast Asia. His administration escalated military engagement significantly, moving beyond the advisory role that had previously been taken during the Eisenhower and Kennedy administrations. The Gulf of Tonkin Resolution in 1964, which Johnson used to justify increased military action, allowed for the deployment of combat troops. As a result, Johnson's military strategy led to a substantial escalation of U.S. involvement in the Vietnam War, which included large ground forces and intensified air strikes against North Vietnam.

In contrast, previous presidents had focused more on political and diplomatic solutions, attempting to contain communism through aid or limited military involvement rather than committing large numbers of U.S. forces to active combat operations. Johnson's approach not only changed the nature of U.S. intervention but also set the stage for a prolonged conflict that would later draw significant domestic opposition and have lasting implications for U.S. foreign policy.