A U.S. Marine with an automatic rifle, left, guards the wall of the U.S. Embassy compound in Saigon, as Vietnamese citizens try to scale it to reach evacuation helicopters on May 1, 1975. There was a wild frenzy to escape the South Vietnamese capital as communist troops entered the city at the end of the war. (Neal Ulevich/Associated Press)

The Nov. 17 obituary for Melvin R. Laird, “Defense secretary led withdrawal from Vietnam,” said about the Vietnam War that “communist forces prevailed in 1975 because the South could not overcome internal divisions and government corruption.” That is wrong. Both sides were entirely dependent on outside sources for the wherewithal needed to conduct operations. The war was lost because Congress drastically reduced aid to South Vietnam while North Vietnam was receiving greatly increased support from its communist patrons.

Lewis Sorley, Potomac

Melvin R. Laird’s obituary correctly reported that “the effort to withdraw U.S. troops gradually while building South Vietnam’s military into a force that could support itself” — known as Vietnamization — “was a success.” But the obituary attributed South Vietnam’s 1975 defeat to its “internal divisions and governmental corruption.” After the United States had withdrawn all its ground troops, Hanoi, on March 30, 1972, launched the largest offensive of the war, with the equivalent of 23 divisions equipped with hundreds of Soviet tanks, heavy artillery, rockets and other arms.

By fall, however, North Vietnamese troops were facing certain defeat, having already lost twice as many men as the United States had lost in the entire war. (The United States had provided massive air support.) To stave off defeat, Hanoi lured my boss Henry Kissinger into negotiations that stopped the fighting and resulted in the immediately violated Paris Peace Accords. Then, Congress reduced aid to South Vietnam by two-thirds and next, on June 4, 1973, banned all U.S. military action in Indochina. These were the actions that ensured the defeat, in 1975, of the South Vietnamese army, which depended heavily on U.S. air support and on U.S. military aid.

William Lloyd Stearman, North Bethesda

The writer is a retired Foreign Service officer.