A little over two weeks after the first Marine landings at Danang, Assistant Secretary of Defense John McNaughton commented on the growing influence of the Vietcong within South Vietnam. “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….”
By July, the U.S. Mission in Saigon concluded that the Vietcong dominated between 25% and 50% of South Vietnam’s territory. This estimate was almost certainly off the mark. President Nguyen Cao Ky believed the Vietcong controlled 75% of his country’s population, or over 11 million people, almost all of whom lived in the countryside. The Allies still held Saigon, most district and provincial capitals, and the cities along the coastal plain, but South Vietnam’s rich rice-growing regions and the peasants living there had gone over to Communists.
At mid-year, 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. “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 South Vietnamese Army (ARVN) was close to collapse. 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 colour 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.”
Historian and journalist Bernard Fall examined tax delinquency rates in order to gauge the level of GVN influence across South Vietnam. The idea behind his analysis was simple. If the GVN collected taxes from a particular area, it meant it still had administrative control over the people of that area. In 1964, according to Fall, the tax delinquency rate countrywide stood at 74%. Fall postulated from that data that the GVN had control over a mere 26% of South Vietnam’s population. Most of that population resided in the country’s urban centers. Fall’s analysis dovetailed with Ky’s estimate that the Vietcong dominated 75% of South Vietnam’s population. Tax delinquency rates edged higher in 1965 after the Vietcong scored a succession of military victories against the ARVN in May and June.
As a further sign of increasing Communist influence, in the summer of 1965, the Communists tightened their noose around Saigon. 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 travelled by automobile along Route 1 from Saigon to Ham Tan, located north-east of the capital. Even segments of the well-travelled 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 faced daily Vietcong harassment. Daytime travel became dangerous, and nigh time travel impossible. 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-1965.
To limit attacks on Allied convoys, and keep U.S. casualties down, General William C. Westmoreland ordered the construction of dozens of airfields across South Vietnam. The MACV chief wanted the country saturated with airfields. Once built, the landing strips would allow U.S. forces to leapfrog over Vietcong territory, rather than try and fight their way through on the ground.
In 1965, U.S. Army engineers constructed dozens of airstrips across South Vietnam. 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 had ceased to function, 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 collapsed in late 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 71, Notes of Meeting,” (Washington, D.C.: GPO, 1996), 191.
 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.