Johnson's opinion on the issue of civil rights put him at odds with other white, southern Democrats. His civil rights legacy was shaped by signing the Civil Rights Act of 1964, the Voting Rights Act of 1965, and the Civil Rights Act of 1968. During his presidency, the American political landscape transformed significantly,[3] as white southerners who were once staunch Democrats began moving to the Republican Party[4] and black voters began moving to the Democratic Party.[5][6] Because of his domestic agenda, Johnson's presidency marked the peak of modern liberalism in the United States.[7]
Johnson's presidency took place during the Cold War and his foreign policy prioritised containment of communism. Prior to his presidency, the U.S. was already involved in the Vietnam War, supporting South Vietnam against the communist North. Following a naval skirmish in 1964 between the United States and North Vietnam, Congress passed the Gulf of Tonkin Resolution, which granted Johnson the power to launch a full-scale military intervention in South East Asia. The number of American military personnel in Vietnam increased dramatically, and casualties soared among U.S. soldiers and Vietnamese civilians. Johnson also expanded military operations in neighboring Laos to destroy North Vietnamese supply lines. 