American Military History, Volume 2 by Richard W. Stewart

The U.S. troop withdrawals began in the summer of 1969, when two brigades of the 9th Infantry Division pulled out of III and IV Corps and a regiment of the 3d Marine Division departed from northern I Corps. These units were selected because they were considered first- rate and would consequently make the reduction in forces credible to all concerned-not just to the governments in Hanoi and Saigon but also to the American public. The 9th Division was chosen, according to General Abrams, because the war south of Saigon had been a South Vietnamese affair for years and was apparently going well.

The marines would be leaving their area of operations to the best South Vietnamese division, the 1st Infantry Division, and to the remainder of their parent Marine unit, now reinforced along the demilitarized zone by the heavy brigade of the U.S. Army's 5th Division. The northernmost provinces, by all accounts, were thus also secure. The one area of the country where Abrams refused to thin out his forces was the territory north and west of Saigon, the arc protecting the capital. Saigon was the ultimate war prize, and everything depended on its security, from holding fast to public support in the United States and building a negotiating advantage to giving the South Vietnamese time to grow strong in their own defense. Abrams was not prepared to gamble Saigon's security on a military ex- periment, at least not yet.