Litter of rifles for which there was no ammunition or vehicles for which there were no spare parts because the Democrat controlled congress terminated the sending of supplies of ammunition and replacement parts to the South Vietnamese government and military as President Nixon had promised would continue. Thus the formal full-scale invasion of the south by the North Vietnamese Regular Army was able to overrun the ARVN as it ran out of the means to fight.
Why would the ARVN fight knowing defeat was inevitable?
The North tried the same attack in 1973-- with US air support & advisors, the ARVN defeated the invasion. Giap told the Central Committee at that time that North Vietnam would never win as long as the US supported the South. He was relieved of command.
The North only won because the communist traitors in the Democratic Party and media bamboozled the US public into cutting off aid.
One of the consequences of the fall of South Vietnam was the Soviet invasion of Afghanistan: so we are still feeling the consequences of the treason of the Democrats almost 40 years afterwards.
All too true. When we left, massiver aid was preposed, but congress disposed.