After the fall of South Vietnam in 1975, there was an acrimonious debate over who lost the Vietnam War. Many in the military and the Republican Party subscribed to a “stabbed in the back” myth, blaming politicians and the media for supposedly preventing the armed forces from defeating North Vietnam. Many liberals, on the other hand, argued that it was a war the United States should not have fought and could not have won.

Afghanistan isn’t lost — yet — but with the Taliban advancing rapidly, the debate over “who lost Afghanistan?” has already begun. Republicans, ignoring that it was President Donald Trump who began the withdrawal, are blaming President Biden for “a disaster in the making.” Biden defended himself last week by claiming that we had achieved our “objectives” — “to get the terrorists who attacked us on 9/11 and to deliver justice to Osama Bin Laden” — and, beyond that, “it’s up to the people of Afghanistan to decide on what government they want.” Retired Lt. Gen. H.R. McMaster, Trump’s national security adviser, jumped in to blame media “disinterest and defeatism” for creating the “conditions for capitulation,” while progressive MSNBC host Mehdi Hasan argued “the original invasion itself was an outrage, given there were no Afghans aboard any of the 4 planes” on Sept. 11, 2001.

Suffice it to say there is plenty of blame to go around for what is likely to be remembered as the second major war — after Vietnam — that the United States has lost. But it shouldn’t fall on the media. McMaster himself once wrote that the “war in Vietnam” was not “lost on the front pages of the New York Times,” and the same is true in Afghanistan. Negative news articles reflect reality — they don’t create it.

The real blame falls squarely on politicians and generals — both American and Afghan. A succession of U.S. presidents made one mistake after another. While George W. Bush was right to go into Afghanistan (which is where the attack originated, even if there were no Afghans on the 9/11 planes), he was wrong to pivot to a war of choice in Iraq. Barack Obama implemented a halfhearted, time-limited troop surge that encouraged the Taliban to wait it out. Trump negotiated an agreement that demanded next to nothing of the Taliban in return for a U.S. pullout. Biden, instead of pointing out that the Taliban had failed to break ties with al-Qaeda, moved ahead with the withdrawal anyway despite the likelihood that Afghanistan will once again become a terrorist haven.

The U.S. military cannot escape blame for this fiasco. As The Post’s Afghanistan Papers series pointed out, U.S. forces failed to “build a competent Afghan army and police force” or to tell the truth about how badly the war was going. This was more a matter of self-deception than of conscious lying. With its gung-ho, can-do ethos, the U.S. military is inherently inclined to highlight evidence of “progress,” however chimerical, instead of focusing on far more pervasive problems.

As poorly as U.S. politicians and military leaders performed, their Afghan counterparts have been far worse. The reasons that so much of the Afghan army appears to be crumbling in the face of the enemy — just as the Iraqi army did in 2014 — are poor leadership and pervasive corruption. As a former Afghan finance minister told the New York Times: “The mismanagement has led us to where we are today.” Even now, with the enemy practically at the gates, the Afghan elite continue to squabble among themselves rather than unite to save the nation.

Given the dysfunction and corruption of the Afghan political class, it is tempting to simply wash our hands of the country, as Biden is now doing, by suggesting that we’ve done enough and now it’s up to them. There is a logic to this argument, but in Afghanistan, the United States is itself complicit in misgovernance — just as we were in South Vietnam.

For 20 years, we pumped untold billions into Afghanistan and cut unsavory deals with corrupt warlords. In the process, we empowered abusive crooks while making the Afghan military reliant on our support. The sudden withdrawal of U.S. air power has been a crippling blow, not only militarily but also psychologically, because we are also withdrawing the contractors who keep Afghan aircraft flying. By leaving, we’re not giving the people of Afghanistan the opportunity to decide how they want to be governed, as Biden said. We’re giving a barbaric insurgency the opportunity to oppress them.

After having invested so much for so long in Afghanistan, we cannot now escape responsibility for its fate. In 1975, a U.S. Army colonel famously told a North Vietnamese colonel, “You know, you never beat us on the battlefield.” His counterpart responded, “That may be so, but it is also irrelevant.”

Indeed. Guerrillas prevail not by outfighting but by outlasting a more powerful foe. The Taliban has done just that. It has not yet defeated the government in Kabul, but it has already defeated the one in Washington. Let the recriminations and finger-pointing begin. If Vietnam is any indication, the Afghanistan “blame game” could roil U.S. politics for decades to come.