 The total number of U.S. forces in South Vietnam dropped to 196,700 on October 29, 1971, the lowest level since January 1966.On November 12, 1971, Nixon set a February 1, 1972 deadline for the removal of another 45,000 troops.Vietnamization received another severe test in the spring of 1972 when the North Vietnamese launched a massive conventional offensive across the Demilitarized Zone.