In the dangerous and changing world of the Cold War, a massive military buildup was necessary to prevent the expansion of communism in Southeast Asia, according to the Domino Effect theory. At the end of Dwight D Eisenhower’s second term in Office, the number of American military advisors had been increased to 900, using as air transportation 7 Sikorsky H-19 and 3 Piasecki H-21 helicopters. In 1962, however, Democratic President, John F Kennedy authorized the escalation of US troops through the signature of a “National Security Action Memorandum”; thus, by mid 1963 there were 16,000 US troops, which included Green Berets units, in the region. Although these Special Forces men had been sent as militar advisors, they actually engaged Vietcong guerrillas in South Vietnam in combat action. Along with these US militar personnel, C-119 Flying Boxcar and C-130 Hercules cargo aircraft had been sent to Southeast Asia and several thousands of M2 4.2-in mortars and M1919 Browning machine guns, which were supplied to the South Vietnamese Army’s Infantry.
In August 1964, after the Gulf of Tonkin Incident, President Johnson decided to fully get involved in Vietnam, sending the first US combat troops. So, by late December 1964, there were approximately 30,000 US Army soldiers and USMC troops fighting against the Vietcong insurgents and North Vietnamese Army units that infiltrated South Vietnam. As the war wore on, the fighting became even more vicious and the enemy more elusive and ubiquitous at the same. Since China and North Vietnam had been supplying the Vietcong with large quantatity of weapons and men through the Ho Chi Minh Trail, the Johnson Administration was forced to send even more troops and armament to Southeast Asia and escalate the bombing of North Vietnam as the United States got bogged down in a Cold War quagmire. By 1968, more than 550,000 US Army, USMC, and USAF soldiers and pilots had been deployed in Vietnam. However, by mid 1968, after the Tet Offensive, the war had become very unpopular. As a result, the US Senate would cut back the military budget assigned to Vietnam that year. During the Nixon Administration, a policy of vietnamization of the war would be implemented as the US troops would be withdrawn from Southeast Asia in stages to be replaced by South Vietnamese Army units.
Total US Military Buildup in Vietnam
Military vehicles: 2,500 (including M113 armored carriers, and M48 Patton and M551 Sheridan tanks)
Artillery pieces: 3,700
Helicopters: 7,500 (including 6,000 UH-1 Hueys and AH-1 Cobras)
Fighter aircraft: 800 (F-4, F-105, F-100, F-101)
Bombers and ground attack: 500 (USAF B-52s, USNavy A-4 Skyhawk, USArmy AC-130 Spectres, and others)
Cargo aircraft: 350