<P> Vietnamization was again tested by the Easter Offensive of 1972 , a massive conventional NVA invasion of South Vietnam . The NVA and Viet Cong quickly overran the northern provinces and in coordination with other forces attacked from Cambodia , threatening to cut the country in half . U.S. troop withdrawals continued . American airpower responded , beginning Operation Linebacker , and the offensive was halted . However , it became clear that without American airpower South Vietnam could not survive . The last remaining American ground troops were withdrawn by the end of March 1973 ; U.S. naval and air forces remained in the Gulf of Tonkin , as well as Thailand and Guam . </P>
<P> Vietnamization was again tested by the Easter Offensive of 1972 , a massive conventional NVA invasion of South Vietnam . The NVA and Viet Cong quickly overran the northern provinces and in coordination with other forces attacked from Cambodia , threatening to cut the country in half . U.S. troop withdrawals continued . American airpower responded , beginning Operation Linebacker , and the offensive was halted . However , it became clear that without American airpower South Vietnam could not survive . The last remaining American ground troops were withdrawn by the end of March 1973 ; U.S. naval and air forces remained in the Gulf of Tonkin , as well as Thailand and Guam . </P>
when did the united states withdrew from vietnam
when did the united states withdrew from vietnam
by the end of March 1973
by the end of March 1973