The Vietnam War did not involve communism.
Vietnam War . The North Vietnamese army was supported by the Soviet Union , China and other communist allies and the South Vietnamese army was supported by the United States , South Korea , Australia , Thailand and other anti-communist allies . The U.S. government viewed its involvement in the war as a way to prevent a communist takeover of South Vietnam . This was part of the domino theory of a wider containment policy , with the stated aim of stopping the spread of communism worldwide . Operations crossed international borders : bordering areas of Laos and Cambodia were heavily bombed by U.S. forces as American involvement in the war peaked in 1968 , the same year that the communist side launched the Tet Offensive . Gradual withdrawal of U.S. ground forces began as part of `` Vietnamization '' , which aimed to end American involvement in the war while transferring the task of fighting the communists to the South Vietnamese themselves .