1970 in the Vietnam War

The United States continued its unilateral withdrawal of forces from South Vietnam notwithstanding the lack of progress at the Paris Peace Talks. The removal of Prince Norodom Sihanouk from power in Cambodia in March and his replacement by General Lon Nol, began the Cambodian Civil War. South Vietnamese and U.S. forces entered Cambodia in late April to attack People's Army of Vietnam (PAVN) and Vietcong (VC) bases and supply lines there which had long been used to support the insurgency in South Vietnam. The expansion of the war revitalized the antiwar movement in the U.S. and led to the Kent State shootings and Jackson State killings in May. While U.S. ground forces withdrew from Cambodia at the end of June and legislation was passed to prevent their reintroduction, the South Vietnamese conducted operations in Cambodia for the rest of the year and the U.S. provided air support and military aid to the Cambodian government. Despite this support the Cambodians lost control of vast areas of the country to the PAVN. Within South Vietnam the second half of the year saw a reduction in large U.S. operations with the focus shifting to pacification and population security and supporting Vietnamization. The PAVN/VC generally reverted to sapper attacks and attacks by fire but they fought hard to defend their base areas and infiltration routes.