Video: 'President Richard Nixon Address to the Nation on the Situation in Southeast Asia, April 30, 1970'

(Thursday, April 30, 1970, 9:00 p.m. EDT; during the Cambodian Campaign, part of the Vietnam War, Cambodian Civil War, Indochina Wars and the Cold War) — In a sharp departure from the previous conduct of war in Southeast Asia, U.S. President Richard Nixon announced tonight that he was sending United States combat troops into Cambodia for the first time.

Video: 'Vietnam: A Television History - Homefront USA [10/11]' (Cambodia Campaign at 43:59)

Even as the President was addressing the nation on television, several thousand American soldiers were moving across the border from South Vietnam to the Fishhook area of Cambodia, some 50 miles northwest of Saigon, to attack what Nixon described as “the headquarters for the entire Communist military operation in South Vietnam.”

Video: 'Vietnam: A Television History - Cambodia and Laos [8/11]' (Cambodian Campaign at 22:19)

White House sources said they expected the operation to be concluded in six to eight weeks. They said its primary objective was not to kill enemy soldiers but to destroy their supplies and drive them from their sanctuaries.

Video: 'Our World Spring 1970 Part 1' (Cambodian Campaign at 7:32)