Arthur Herman feels that we have yet to learn the lessons of Vietman

as he writes:

Actually, the U.S. had won the war in Vietnam on the battlefield, just as the surge has done today in Iraq. Over Easter 1972, South Vietnamese forces, backed by U.S. airpower, crushed the last communist offensive, killing nearly 100,000 North Vietnamese troops.

The North was forced to sign peace accords in Paris recognizing the Republic of South Vietnam. The last 2,500 U.S. support troops went home. What they left was a fragile but sustainable peace, and an elected government in Saigon that was growing stronger every month.

After nearly two decades of devastating war and 58,000 American combat deaths, the U.S. left Southeast Asia. As the last helicopter lifted off from Saigon, the New York Times's Sydney Schanberg wrote an article with the title, "Indochina Without Americans: For Most, a Better Life." And the Times's columnist Anthony Lewis asked, "what future could possibly be more terrible than the reality" of a war that had cost so much in lives and treasure?

With the North Vietnamese Communists and the Khmer Rouge taking over, the world was about to find out.

At least 65,000 Vietnamese were murdered or shot after "liberation" – the equivalent in terms of Vietnam's population at the time, of killing three-quarters of a million people in today's U.S. The new communist regime ordered somewhere between one- third to one-half of South Vietnam's population to pass through its "re-education" camps, where perhaps as many as 250,000 died of disease, starvation, or were worked to death (the last inmates were not released until 1986).

That number does not include the thousands of "boat people" who tried to flee the totalitarian nightmare of communist Vietnam, and perished at sea.

Cambodia's fate was even worse. At least one and a half million innocent Cambodians were butchered or starved to death in the Khmer Rouge's killing fields and re-education camps, put to death by a fanatical regime that believed that anyone who wore eyeglasses must have "bourgeois intellectual tendencies" and be shot.

The scale of moral collapse and suffering went beyond Indochina. The pullout had a ripple effect on U.S. power and prestige, just as the proponents of the so-called "domino theory" had warned. American foreign policy, crippled by remorse and self-doubt, stood helplessly as others rushed into the power vacuum.

Marxist-Leninist regimes emerged not only in Vietnam, Cambodia, and Laos, but in Ethiopia and Guinea Bissau (1974), Madagascar, Cape Verde, Mozambique, and Angola (1975), Afghanistan (1978), and Grenada and Nicaragua (1979). Soviet troops were welcomed in Fidel Castro's Cuba for the first time since the 1962 missile crisis. Cuban troops traveled freely to Africa to prop up Marxist regimes there.

In 1979 the Ayatollah Khomeini was able to establish his brutal theocratic rule over Iran, confident that America, having learned "the lessons of Vietnam," would never intervene.