When Richard M. Nixon became president in 1969, he profoundly changed U.S. foreign policy. The new theme was withdrawal from commitments around the globe. Nixon revived the kind of nationalist, unilateral foreign policy that, since Theodore Roosevelt, presidents of his political tradition had preferred. With Henry Kissinger as an advisor and later as secretary of state, he began a kind of balance-of-power diplomacy. He preferred to keep the United States free of lasting commitments (even to former allies) so that it could move back and forth between the other four power centers - Europe, the USSR, China, and Japan - and maintain world equilibrium.

Nixon soon announced his "Vietnamization" policy, which meant a slow withdrawal of American forces and a heavy building up of the South Vietnam army. Nonetheless, in the 3 years 1969-71, 15,000 more Americans died fighting in Vietnam. In April 1970, Nixon launched a huge invasion of Cambodia in a vain attempt to clear out communist "sanctuaries."

Then, most dramatically, he deflected world attention by ending the long American quarantine of Communist China, visiting Beijing in February 1972 for general discussions on all matters of mutual concern - a move that led to the establishment (1979) of diplomatic relations. At the same time, he continued the heavy bombing attacks on North Vietnam that he had reinstituted in late 1971. He brushed aside as "without binding force or effect" the congressional attempt to halt American fighting in Vietnam by repealing the Tonkin Gulf Resolution of 1964, which had authorized Johnson to begin military operations. Nixon asserted that as commander in chief he could do anything he deemed necessary to protect the lives of American troops still in Vietnam.

In May 1972, Nixon became the first American president to consult with Soviet leaders in Moscow, leaving with major agreements relating to trade, cooperation in space programs and other fields of technology, cultural exchanges, and many other areas. He became more popular as prosperity waxed and as negotiations with the North Vietnamese in Paris seemed to be bringing the Vietnam War to a halt. In 1972 the Democrats nominated for the presidency Sen. George McGovern of South Dakota, a man who for years had advocated women's rights, black equality, and greater power for the young. With the nation's increasingly conservative cultural mood and the trend in Vietnam, Nixon won a massive landslide victory. In January 1973, Nixon announced a successful end to the Vietnamese negotiations: a cease-fire was established and an exchange of prisoners provided for.