Army

On October 26, 1956, the military was reorganized by the administration of President Ngo Dinh Diem who established the Army of the Republic of Vietnam (ARVN, pronounced "arvin"). Early on, the focus of the army was combatting the guerrilla fighters of the National Front for the Liberation of South Vietnam (NLF, also known as the Viet Cong) an insurgent movement formed to oppose the Diem administration. The United States, under President John F. Kennedy sent advisors and a great deal of financial support to aid ARVN in combating the NLF resistance. ARVN and President Diem began to be criticized by the foreign press when the troops were used to crush southern religious groups like the Cao Dai and Hoa Hao as well as to raid Buddhist temples, which Diem claimed were harboring Communist guerrillas.

In 1963 Ngo Dinh Diem was killed in a coup d'etat carried out by ARVN officers led by Duong Van Minh ('Big Minh'). In the confusion that followed Big Minh took power, but was only the first in a succession of ARVN generals to assume the presidency of South Vietnam in a period of intense political instability. During these years, the United States began taking full control of the war against the NLF and the role of the ARVN became less and less significant. They were also plagued by continuing problems of severe corruption among the officer corps. Although the U.S. was highly critical of them, the ARVN continued to be entirely U.S. armed and funded.

The value of the ARVN was highly questionable in this period. In 1963 at the Battle of Ap Bac some 1,400 ARVN troops were defeated by only 350 NLF guerrillas. The battle of Dong Xoai in 1965 was another humiliating ARVN defeat. Although they always outnumbered their nationalist enemies, most were inexperienced, poorly trained, and not motivated to fight hard for the generals and politicians behind them. Generals tended to be political appointees and corruption was rampant. Their relations with the civilian population were never good and relations with the U.S. military were often very cold.

Starting in 1969, President Richard M. Nixon started the process of "Vietnamization," pulling out American forces and leaving the ARVN to fight the war against the People's Army of Vietnam (PAVN). Slowly, ARVN began to expand from its counter-insurgency role to become the primary ground defense against the NLF and North Vietnamese. From 1969–1971 there were about 22,000 ARVN combat deaths per year. Starting in 1968, South Vietnam began calling up every available man for service in the ARVN, reaching a strength of a million soldiers by 1972. In 1970 they performed well in Cambodia and were executing 3 times as many operations as they had during the American war period. However, the officer corps was still the biggest problem. Leaders were often poorly trained, inept and the equipment continued to sub-standard as the U.S. tried to upgrade ARVN technology.

Relations with the public also remained poor as their only counter to NLF organizing was to resurrect the 'Strategic Hamlet Program' which many peasants resented. Disapproving Americans called this "barbed wire diplomacy." However, forced to carry the burden left by the Americans, the South Vietnamese army actually started to perform rather well and in 1970 was winning the war against the Communists, though with continued American air support. The exhaustion of the North was becoming evident and the Paris talks gave some hope of a negotiated peace if not a victory.

The most crucial moment of truth for the ARVN came with General Vo Nguyen Giap's 1972 "Easter Offensive," the first all-out invasion of South Vietnam by the communist North. It was code-named "Nguyen Hue" after the historic Vietnamese hero who defeated the Chinese in 1778. The assault combined infantry wave assaults, artillery and the first massive use of tanks by the North Vietnamese. ARVN took heavy losses, but to the surprise of many, managed to hold their ground.

U.S. President Richard Nixon dispatched more bombers to provide air support for ARVN when it seemed that South Vietnam was about to be overrun. In desperation, President Nguyen Van Thieu fired the incompetent General Hoàng Xuân Lãm and replaced him with ARVN's best commander, General Ngo Quang Truong. He gave the order that all deserters would be executed and pulled enough forces together so that the North Vietnamese army (PAVN) failed to take Hue. Finally, largely as a result of U.S. air and naval support, as well as some surprising determination by the ARVN soldiers, the Easter Offensive was halted.

After the signing of the Paris Peace Accords in 1973 all U.S. military forces withdrew from South Vietnam and the war officially ended, however clashes between ARVN and NLF forces continued.

In 1975 the PAVN again invaded the South. Lacking U.S. air support the ARVN could not hold them back. City after city fell to the Communists with ARVN soldiers joining the civilians trying to flee south. The North called this the "Hồ Chí Minh Campaign." All resistance crumbled. Faced with few viable options, the South tried to form a coalition government that would be palatable to the Communists, one that favored negotiated peace and neutrality. The new coalition government was headed by General Duong Van Minh (Big Minh), one of the organizers of the coup in November 1963, with the full support of the CIA and President Kennedy, that killed President Ngo Dinh Diem. General Cao Van Vien, then Colonel and Commander of the Airborne Brigade, had been captured and held by the Big Minh faction and threatened with execution unless he ordered his troops to join the coup. He refused and was held captive until the end of the coup and was released only because of his close friendship with one of the coup leaders.

Because the new coalition government would be headed by Big Minh, General Vien immediately submitted his resignation to then President of South Vietnam Tran Van Huong, who succeeded President Thieu as President. President Huong, knowing the 1963 coup history, granted General Vien's resignation request (Vien had submitted his resignation to President Thieu many times and had always been turned down).General Vien then escaped to the US as a civilian once his resignation was effective and formalized.

The situation in South Vietnam deteriorated.

The ARVN tried to defend Xuan Loc, their last line before Saigon. These men fought very well, but it was not enough. The men were greatly outnumbered and overwhelmed by the entire army of North Vietnam. Xuan Loc was taken and on April 30, 1975, initiated the Fall of Saigon. The army of the Democratic Republic of Vietnam captured the city, placing the Vietnam National Liberation Front flag over the Independence Palace even though the NLF had accomplished almost nothing during the battles and had almost no authority within the country. General Duong Van Minh, recently appointed president by Tran Van Huong, unconditionally surrendered the city and government bringing the Republic of Vietnam and also the Army of the Republic of Vietnam to a final end.