The Cambodian campaign (also known as the Cambodian incursion and the Cambodian invasion) was a brief series of military operations conducted in eastern Cambodia in 1970 by South Vietnam and the United States as an extension of the Vietnam War and the Cambodian Civil War. Thirteen major operations were conducted by the Army of the Republic of Vietnam (ARVN) between 29 April and 22 July and by U.S. forces between 1 May and 30 June 1970.

The objective of the campaign was the defeat of the approximately 40,000 troops of the People's Army of Vietnam (PAVN) and the Viet Cong (VC) in the eastern border regions of Cambodia. Cambodian neutrality and military weakness made its territory a safe zone where PAVN/VC forces could establish bases for operations over the border. With the US shifting toward a policy of Vietnamization and withdrawal, it sought to shore up the South Vietnamese government by eliminating the cross-border threat.

A change in the Cambodian government allowed an opportunity to destroy the bases in 1970, when Prince Norodom Sihanouk was deposed and replaced by proU.S. General Lon Nol. A series of South VietnameseKhmer Republic operations captured several towns, but the PAVN/VC military and political leadership narrowly escaped the cordon. The operation was partly a response to a PAVN offensive on 29 March against the Cambodian Army that captured large parts of eastern Cambodia in the wake of these operations. Allied military operations failed to eliminate many PAVN/VC troops or to capture their elusive headquarters, known as the Central Office for South Vietnam (COSVN) as they had left a month prior, but the haul of captured material in Cambodia prompted claims of success.

Richard Milhous Nixon (January 9, 1913 – April 22, 1994) was the 37th president of the United States, serving from 1969 to 1974. He was a member of the Republican Party who previously served as a representative and senator from California and was the 36th vice president from 1953 to 1961. His five years in the White House saw the end of U.S. involvement in the Vietnam War, détente with the Soviet Union and China, the first manned Moon landings, and the establishment of the Environmental Protection Agency. Nixon's second term ended early, when he became the only president to resign from office, following the Watergate scandal.

Nixon was born into a poor family of Quakers in a small town in Southern California. He graduated from Duke Law School in 1937, practiced law in California, then moved with his wife Pat to Washington in 1942 to work for the federal government. After active duty in the Naval Reserve during World War II, he was elected to the House of Representatives in 1946. His work on the Alger Hiss Case established his reputation as a leading anti-Communist, which elevated him to national prominence, and in 1950, he was elected to the Senate. Nixon was the running mate of Dwight D. Eisenhower, the Republican Party's presidential nominee in the 1952 election, and served for eight years as the vice president. He ran for president in 1960, narrowly lost to John F. Kennedy, then failed again in a 1962 race for governor of California. In 1968, he made another run for the presidency and was elected, defeating Hubert Humphrey and George Wallace in a close contest.

Nixon formally ended American involvement in Vietnam combat in 1973, and with it, the military draft, that same year. His visit to China in 1972 eventually led to diplomatic relations between the two nations, and he also then concluded the Anti-Ballistic Missile Treaty with the Soviet Union. In step with his conservative beliefs, his administration incrementally transferred power from the federal government to the states. Nixon's domestic policy saw him impose wage and price controls for 90 days, enforce desegregation of Southern schools, establish the Environmental Protection Agency, and begin the War on Cancer. Additionally, his administration pushed for the Controlled Substances Act and began the War on Drugs. He also presided over the Apollo 11 Moon landing, which signaled the end of the Space Race. He was re-elected with a historic electoral landslide in 1972 when he defeated George McGovern.

In his second term, Nixon ordered an airlift to resupply Israeli losses in the Yom Kippur War, a war which led to the oil crisis at home. By late 1973, the Nixon administration's involvement in the Watergate eroded his support in Congress and the country. On August 9, 1974, facing almost certain impeachment and removal from office, Nixon resigned the presidency. Afterwards, he was issued a pardon by his successor, Gerald Ford. In his almost 20 years of retirement, Nixon wrote his memoirs and nine other books and undertook many foreign trips, rehabilitating his image into that of an elder statesman and leading expert on foreign affairs. He suffered a debilitating stroke on April 18, 1994, and died four days later at age 81. Surveys of historians and political scientists have ranked Nixon as a below-average president. Evaluations of him have proven complex, as the successes of his presidency have been contrasted with the circumstances of his departure from office.