In 1965, South Vietnam teetered on the edge of collapse; and top American officials, as well as independent military analysts, knew it.
In late March 1965, a little over two weeks after the first Marine landings at Danang, Assistant Secretary of Defense John McNaughton commented on the strength of the Vietcong within South Vietnam. He stated, “The situation in general is bad and deteriorating. The VC have the initiative. Defeatism is gaining among the rural population…GVN [Government of South Vietnam] control is shrinking to the enclaves….”
Four months later, U.S. Secretary of Defense McNamara concluded that circumstances in the South had deteriorated even further since McNaughton had written his dire assessment in March. McNamara noted, “The situation in South Vietnam is worse than a year ago (when it was worse than a year before that). After a few months of stalemate, the tempo of the war has quickened. A hard VC [Vietcong] push is now on to dismember the nation and to maul the army…Since June 1, the GVN has been forced to abandon six district capitals; only one has been retaken…Cities and towns are being isolated as fewer and fewer roads and railroads are usable and power and communication lines are cut.” McNamara believed the ARVN was close to disintegration. As for the country as a whole: it was almost lost.
During a meeting in the White House on July 21, 1965, McNamara showed President Johnson a map of South Vietnam. The map depicted areas of Communist and Allied control, which appeared in red and white respectively. The color red covered so much of the map that a worried President Johnson remarked, “Looks dangerous to put US forces in those red areas.” McNamara responded, “You’re right. We’re placing our people with their backs to the sea – for protection.” In other words, the U.S. planned on holding a series of coastal positions in case American ground troops had to call on the U.S. Navy to either help them repulse advancing Communist forces or assist them in beating a hasty retreat from South Vietnam.
In the early and mid-1960s, historian and military analyst Bernard Fall examined tax delinquency rates in order to try and gauge the level of GVN influence across South Vietnam. The idea behind his analysis was simple. If the GVN collected taxes from a particular district, it meant it still had a degree of administrative control over the officials and citizens of that district. In 1964, according to Fall, the GVN failed to collect taxes from seventy-four percent of South Vietnam’s 234 administrative districts. That dismal statistic meant the Saigon regime had an effective administration in only twenty-six percent of South Vietnam’s districts. In 1965, tax delinquency rates edged even higher after the Vietcong scored a succession of military victories against the ARVN in the spring of that year.
In summer 1965, in a further sign of increasing Communist influence within South Vietnam, the Vietcong tightened their noose around Saigon. At that time, Americans risked death or kidnapping at the hands of the Vietcong if they ventured outside the city. Daniel Ellsberg recalled the surprise of U.S. officials when he informed them that he and John Paul Vann had traveled by automobile along Route 1 from Saigon to Ham Tan, located north-east of the capital. Even segments of the well-traveled road between Saigon and Vung Tau had fallen to the guerrillas. The Vietcong had such a strong presence along the road that they charged a toll to the Saigonese venturing to the beaches of Vung Tau. Traffic through the Mekong Delta on Route 4 also faced daily Vietcong harassment. Day-time travel on the road became dangerous, while night-time travel was considered suicidal. That the ARVN could not keep open three major highways, all on the immediate outskirts of the national capital, indicated just how weak the GVN position had become by mid-year.
So many roads across South Vietnam had been severed by the Vietcong that General William C. Westmoreland ordered the construction of dozens of airfields across the country. The airfields allowed recently-arrived U.S. units to leapfrog over Vietcong territory, rather than try and break through on the ground, which would have led to high U.S. casualties. In addition, the proliferation of airfields and the U.S. expeditionary force’s heavy reliance on helicopters and cargo planes for resupply and reinforcement reflected not only the U.S.’s vaunted air mobility, but just how little territory the U.S. and GVN actually controlled in South Vietnam.
In the spring and summer of 1965, the Vietcong were on the cusp of victory in South Vietnam. The South Vietnamese Army was in retreat, the GVN was on life support, and most of the country’s population and territory belonged to the Communists.
If the United States had not intervened with ground troops and airpower, South Vietnam would have fallen to the Communists in 1965 or early 1966. And yet, by directly intervening in the war, President Johnson placed a small number of American troops in an overwhelmingly Communist country, surrounded by a huge, potentially hostile population.
 George C. Herring, ed., The Pentagon Papers, Abridged Edition, (New York: McGraw-Hill, 1993), 116.
 Foreign Relations of the United States, 1964-1968, Volume III, Vietnam, June-December 1965, “Document 67, Memorandum From Secretary of Defense McNamara to President Johnson,” (Washington, D.C.: GPO, 1996), 172-173.
 Foreign Relations of the United States, 1964-1968, Volume III, Vietnam, June-December 1965, “Document 71, Notes of Meeting,” (Washington, D.C.: GPO, 1996), 192.
 Bernard B. Fall, Last Reflections on a War: Bernard B. Fall’s Last Comments on Vietnam, (Mechanicsburg, PA: Stackpole Books, 2000), 199-200.
 Daniel Ellsberg, Secrets: A Memoir of Vietnam and the Pentagon Papers, (New York: Penguin Books, 2002), 122.
 Ibid., 123.