surrounded and assisted by communist organizations elsewhere in Indochina such as the Khmer Rouge and the Pathet Lao, providing credence to the idea that communism was a global and monolithic force. By defeating North Vietnam, communist "tyranny and aggression" could be contained, and the security of Indochina could be preserved, with a unified Vietnam under Southern rule serving as a bulwark against communism in the region. To North Vietnam, the war against the U.S. was simply an extension of their greater war for independence. In their view, the U.S. had merely replaced the French's role as another major-power colonialist obstacle to independence, Vietnamese reunification under Northern rule, and the rise of communism and postcolonial states in Indochina. In 1969, with the Vietnam War becoming increasingly unpopular in the United States, U.S. President Richard Nixon enacted a plan of "Vietnamization", where U.S. military forces withdrew from combat roles and instead only provided intelligence, support, and logistics, with the end goal being a self-sufficient South Vietnam capable of fighting the conflict themselves. By 1972, U.S. forces had largely withdrawn, and their operations were limited to air support, artillery support, advisors, and materiel shipments. On 27 January 1973, the Paris Peace Accords were signed by the U.S., North Vietnam, South Vietnam, and Viet Cong representatives. The Accords called for a ceasefire, withdrawal of all U.S. forces, continuance in place of North Vietnamese troops in the South, and the eventual reunification of Vietnam "through peaceful means". In reality, once the last U.S. combat troops left Vietnam in March 1973, and the U.S. was effectively barred from providing military assistance in Indochina under the 1973 Case–Church Amendment, there was no effective way to prevent North Vietnam from overwhelming South Vietnam's defenses, and the Accords proved unenforceable. North Vietnam and South Vietnam continued to fight for two more years, from 1973 to 1975, but South Vietnam, having to fight without the American support to which it had become accustomed, and lacking the financial support to pay its troops or supply them properly, suffered severe losses of personnel and territory to North Vietnamese forces. In March 1975, North Vietnamese General Võ Nguyên Giáp of North Vietnam, planning to test American resolution, sent General Văn Tiến Dũng to launch an attack on Buôn Ma Thuột; when the U.S. Congress blocked attempts to support South Vietnam, Giáp launched a full-scale invasion of South Vietnam, and by late April, North