Nixon's plan of Vietnamization is considered to have failed because the withdrawal of American troops and aid left the Army of the Republic of Vietnam without proper equipment and training. Tin Nguyen contends that, specifically, Vietnamization failed because it did not allow for the Army of the Republic of Vietnam to increase their number of troops and materials at the same rate as the North Vietnamese Army.
Vietnamization was the name of the Nixon administration's plan to "expand, equip and train South Vietnam's forces and assign to them an ever-increasing combat role at the same time steadily reducing the number of United States combat troops." Nixon, himself, stated that he believed the one of the two crucial components of Vietnamization was "strengthening the armed force of the South Vietnamese in numbers, equipment, leadership and combat skills." It is by that account that Vietnamization is considered a failure.
in 1973 the U. S. reduced funding to the Army of the Republic of Vietnam from $1.6 billion to $1.26 billion. In 1974, funding was reduced again, this time from $1.26 billion to $700 million. The U. S. also reduced their supply of ammunition and spare parts. Ultimately, Nixon became uncommunicative towards the Army of the Republic of Vietnam's leadership which culminated in mistaken tactical withdrawals in March of 1975, in which all ARVN forces from the first and second corps were killed.