And this brings us to the endgame of the endgame. Afghanistan is a relic — though one that keeps reaching out from the crypt. We’ve already moved on. The Pentagon’s “strategic guidance” issued last month stated that “U.S. forces will no longer be sized to conduct large-scale, prolonged stability operations” — read, Iraq and Afghanistan. And while the United States will not be leaving the Middle East, it “will of necessity rebalance towards the Asia-Pacific region.” Washington is pivoting from the Middle East to Asia, and from an immensely frustrating decade of regime change, occupation, nation-building, and counterinsurgency to a much more familiar and, dare we say, rational era of great-power deterrence. The president, and the American people, would like to see the back of Afghanistan.

And the harsh truth is that the West can afford to fail in Afghanistan. The real threat was al Qaeda; and al Qaeda forces in the region were seriously degraded even before the killing of Osama bin Laden. National security officials worry less than they used to that the Taliban would invite jihadists back into Afghanistan. Vice President Joe Biden, who has long argued that the threat was overblown, recently reiterated that, “The Taliban per se is not our enemy.” At this point, the greatest threat that Afghanistan poses to the West is probably not a renascent al Qaeda but a civil war that would reduce the country to howling chaos. That’s what a negotiated settlement would seek to avoid.

So, if all goes well, Afghanistan will be a mess, but not a mess that threatens U.S. national security. That turned out, in the end, to be the story of Vietnam. I would just say one thing, and I think it is something that anyone who has spent time in that woebegone country would feel: The Afghan people deserve better. We invaded their country and we raised their expectations. Perhaps we were wrong to do so; we couldn’t make their government better than it was. But we have an obligation to do what we can — not, chiefly, anymore with soldiers but with aid, trade, diplomacy, and all the other tools of American power. Let us not, in a fit of imperial forgetfulness, abandon Afghanistan as we execute our grateful pivot to Asia.