In March 1965, U.S. troops entered Vietnam. Operation Rolling Thunder began the continuous bombing of North Vietnam and the Ho Chi Minh Trail. Over the next year, the U.S. continued to increase the number of troops in the region. After many battles, the North Vietnamese Army and Viet Minh began the Tet Offensive in January 1968. Attacks were launched in cities across South Vietnam, including Saigon and the invasion of the U.S. Embassy. The Tet Offensive marked the turning point in the war and began the gradual withdrawal of U.S. troops from Vietnam.
After taking backlash about the war, Johnson withdrew from the election. With promises of ending the draft and restoring peace, Richard Nixon took the presidency in November 1968. As Nixon took office, the U.S. pushed for "Vietnamization," giving South Vietnam more responsibility in the war.