But the brute force that the American military brought down on Vietnam was counterproductive. A study from the State Department found that our massive aerial bombing of North Vietnam had failed to achieve its goals and was instead a “sad waste” of civilian casualties and American planes and pilots lost. Secretary of Defense Robert McNamara said of the brutal bombing campaign, “The picture of the world’s greatest super power killing or seriously injuring 1,000 non-combatants a week, while trying to pound a tiny, backward nation into submission on an issue whose merits are hotly disputed, is not a pretty one.” The ground war wasn’t much different. According to some accounts , two civilians were killed for every Viet Cong soldier. There was obviously a fundamental disconnect between implementing search and destroy and winning hearts and minds.

Only the most entrenched revisionists assert that America won the war in Vietnam. Dramatic images of helicopters rescuing American personnel from the roof during the fall of Saigon in 1975 are a symbolic reminder of how real the loss actually was. More common is the view that the Viet Cong defeated American forces without having ever won an actual battle. This myth reveals a lingering pride in the overwhelming force the American military brought against Vietnam.

The shifting goals and strategies not only betrayed the troops fighting in Vietnam but also left a festering wound in the American psyche. By the 1980s, Ronald Reagan and Hollywood were all too eager to address this lingering cynicism, what had come to be called Vietnam syndrome, with a medicine that was equal parts mindless optimism and willful misremembering. How Reagan went about recasting Vietnam as a “winnable” war that was lost because of a lack of will, even a lack of faith in America itself, stands as a warning about how we remember our most recent wars in Iraq and Afghanistan.

In “On War,” Carl von Clausewitz writes that the most important judgment commanders make is figuring out “the kind of war on which they are embarking.” Unfortunately for the tens of thousands of Americans who died and whom we honor this Memorial Day, and the countless more Vietnamese casualties, American leaders were never honest with themselves or anyone else about what they were doing in Southeast Asia. What began in the 1950s as modest support for French colonial forces in Indochina morphed over the next decade into a massive, bloody ground and air campaign that illegally spilled over into neighboring Laos and Cambodia. America, guided by a dark obsession over communist expansion, succumbed to inertia, trying every strategic gambit besides withdrawal.

The impulse to “go ‘Nam” arose when we were forced to hold our fire, to reserve our force, to stand down. It expressed a desire to return to the unrestrained combat of the Vietnam War: body counts, torching villages, search and destroy, a disregard for collateral damage or escalation of force procedures. It was the dark and frustrated fantasy of Americans far from home, occupying a violent and dangerous place. Struggling to comprehend the point of the Rules of Engagement and desperate to get home safe, it’s understandable why the frustrated grunts never made the next logical step: realizing that we lost the Vietnam War.

During my time as an Army infantryman in Iraq, I heard my fellow troops express their frustration in many different ways. There are only so many four-letter words to go around, after all, before the mind takes a more creative bent. One expression stands out in my memory: the suggestion that we should “go ‘Nam” on our enemies.

Haunting the pretense for Vietnam was a conflation of American ideals and American security interests. The two are not the same. For some, that was one of the lessons of the war in Vietnam — without popular support and strategic clarity, foreign adventurism is doomed to failure. And if that was the lesson, then Vietnam was unwinnable. Imposing our own desired political structure on a sovereign nation of people whose culture was completely alien to policy makers didn’t offer the chance of victory.

But not everyone learned the same lesson. As David Corbett writes, “But for … the Reagan administration, Vietnam had a different resonance. They saw that war as a critical failure of American will, and believed that victory had been prevented because troops had not been given ‘permission to win.’ They also believed that this circumspection about the use of military force was undermining American power, and was inviting Soviet aggression around the globe …” The frustrating thing about counterfactuals is that they can’t be disproved. Would the Vietnamese, North and South, have joined hands and decided to take up a parliamentary-style government and capitalist economy if we had killed 100,000 more civilians? I don’t think so. But I can’t prove it.

At any rate, the myth took root. Reagan parlayed the misremembering of Vietnam into politically expedient spectacle. On February 28, 1981, Reagan made his first public statement about the war as president while awarding the Congressional Medal of Honor to a Vietnam veteran. One sentence stands out: “They came home without a victory not because they’d been defeated, but because they’d been denied permission to win.” Reagan’s message implied that there was some achievable level of violence beyond what had already been unleashed on Vietnam that would have turned the tide. Instead of offering an apology to veterans for having to pay the price of America’s reckless policies, Reagan scolded the public for not supporting those policies vigorously enough.

It makes sense that a former actor would come up with a formula that Hollywood would repeat nearly word for word in the Sylvester Stallone-driven “Rambo” film series of the 1980s. In the second installment, “Rambo: First Blood II,” protagonist John Rambo, brooding Vietnam War veteran, is sent on a secret mission back into Vietnam to retrieve prisoners of war that weren’t returned after the Paris Peace Accords. The only question Rambo has for his handler is “Do we get to win this time?” As historian Andrew Bacevich writes “The New American Militarism,” “In this instance, Stallone and his collaborators absorbed and played back (thereby validating) perceptions about Vietnam and attitudes regarding soldiers that coincided neatly with the views and agenda of Reagan and his collaborators in Washington.”

When the guys I served with in Iraq wanted to “go ‘Nam,” they were asking for permission to do whatever it took to win the war and help their buddies make it home. Any understanding of the real history of Vietnam had been obscured under the fog of political posturing and pop culture bombast. It’s more reassuring to believe that you can win, and aren’t being allowed to than to confront the fact that elected officials have trapped you in an unwinnable war.

What’s troubling is that we are now seeing the pattern repeat itself in the way we remember the war in Iraq. It makes little difference if you blame failure on Bush’s tactical choices or Obama’s withdrawal. Both positions imply that the war could have been won. There’s no critique of the efficacy of nation building, of sending massive armies to foreign countries and restructuring them by force. Another irrefutable counterfactual: It might have worked, if only …

You have to wonder if decades from now, young Americans hunkered down in some far-flung corner of the world will find themselves wishing they could “go Iraq” on the enemy.