The reaction to Bush’s invocation of the Vietnam War’s aftermath was swift and critical. John Kerry called the comparison "ignorant." Reporters interviewed several historians who were happy to agree with Kerry. Robert Dalleck called the comparison "a distortion":

What is Bush suggesting? That we didn’t fight hard enough, stay long enough? That’s nonsense. It’s a distortion… We’ve been in Iraq longer than we fought in World War II. It’s a disaster, and this is a political attempt to lay the blame for the disaster on his opponents. But the disaster is the consequence of going in, not getting out.

USA Today asked Stanley Karnow: "Vietnam was not a bunch of sectarian groups fighting each other, as in Iraq. In Cambodia, the Khmer Rouge toppled a U.S.-backed government. Does he think we should have stayed in Vietnam?"

Bugs Bunny had a name for people like this: "maroons." And Alan Dershowitz once wrote a book about them entitled Chutzpah! Of course in criticizing Bush’s reference to Vietnam, they are comparing apples and oranges. If they don’t see this, they are fools. If they do—which is more likely—they are dishonest. Take your pick.

The fact is that opponents of the war have drawn the Vietnam analogy like a gun, seeking from the very beginning to argue that Iraq and Vietnam were analogous. Ted Kennedy famously called Iraq "George Bush’s Vietnam."

I have argued on several occasions that the parallels between the two conflicts at the operational and strategic levels of war were nonsensical. But that has never stopped the opponents of the current war from invoking the conventional Vietnam War narrative, which goes something like this: The U.S. was predestined to lose the Vietnam War because the Vietnamese Communists were too determined, the South Vietnamese too corrupt, and Americans were incapable of fighting the kind of war that would have been necessary to prevail. Accordingly, "orthodox" Vietnam historians often act as if Hanoi had pursued a course of action with little regard for what the United States did.

It is clear that those who invoke Vietnam in discussing Iraq accept the orthodox narrative. But revisionists such as Bob Sorely in A Better War and Mark Moyar in Triumph Forsaken have called the conventional narrative into question. They and others have shown that Hanoi, as Clausewitz would have predicted, responded to American actions. Moyar’s thesis is that the U.S. defeat was far from inevitable; the United States had ample opportunities to ensure the survival of South Vietnam but failed to develop the proper strategy to do so. By far the greatest mistake the Americans made was to acquiesce in the November 1963 coup that deposed Diem, a decision that "forfeited the tremendous gains of the preceding nine years and plunged the country into an extended period of instability and weakness."

Sorley argues along the same lines. Building on his excellent biographies of Army generals Creighton Abrams and Harold Johnson, Sorley examined the largely neglected later years of the conflict and concluded that the war in Vietnam "was being won on the ground even as it was being lost at the peace table and in the US Congress."

The fact is that the outcome of a war is not predetermined. Who wins and who loses are determined in the final instance by the respective actions of the combatants. Victory or defeat depends on decisions actually made and strategies actually implemented. We came close to victory in Vietnam, but then threw it away.

The 1972 Easter Offensive provided the proof that Vietnam could survive, albeit with U.S. air and naval support, at least in the short term. The Easter Offensive was the biggest North Vietnamese offensive push of the war, greater in magnitude than either the 1968 Tet offensive or the final assault of 1975. Despite inevitable failures on the part of some units, all in all, the South Vietnamese fought well. Then, having blunted the Communist thrust, they recaptured territory that had been lost to Hanoi. Finally, so effective was the eleven-day "Christmas bombing" campaign (LINEBACKER II) later that year that the British counterinsurgency expert, Sir Robert Thompson exclaimed, "you had won the war. It was over."

Three years later, despite the heroic performance of some ARVN units, South Vietnam collapsed against a much weaker, cobbled-together PAVN offensive. What happened to cause this reversal?

First, the Nixon administration, in its rush to extricate the country from Vietnam, forced South Vietnam to accept a ceasefire that permitted North Vietnamese forces to remain in South Vietnam. Then in an act that still shames the United States to this day, Congress cut off military and economic assistance to South Vietnam. Finally, President Nixon resigned over Watergate and his successor, constrained by congressional action, defaulted on promises to respond with force to North Vietnamese violations of the peace terms.

Of course the President’s reference to Vietnam did not have to do with operational art or strategy but with the consequences of defeat: the abandonment of allies to the tender mercies of Vietnamese and Cambodian Communists, resulting in the death of millions in Cambodia and thousands in Vietnam, the "boat people," and re-education camps. This abandonment of our Vietnamese allies was a massive moral failure on the part of the United States. It is one we should not repeat in Iraq.

Mackubin T. Owens is an adjunct fellow of the Ashbrook Center and a professor of strategy and force planning at the Naval War College in Newport, R.I. He led a Marine infantry platoon in Vietnam in 1968-1969.