President Joe Biden will soon announce that U.S. forces will withdraw from Afghanistan by September 11, 2021, the Washington Post reported Tuesday, breaking a peace deal signed by the United States and the Taliban last year.

Under the 2020 Doha agreement, U.S. forces were supposed to have left Afghanistan by May 1, 2021.

In a statement today,** the Quincy Institute called the move an “historic pivot in post-Cold War U.S. policy — away from waging endless war as a default and toward a more militarily restrained approach to national security.”

Stephen Wertheim, QI’s director of Grand Strategy, weighed in: “These are extremely promising measures, not only on their own terms, but for changing U.S. foreign policy as a whole,” he said. “For three decades, successive administrations have entangled the United States in armed conflicts and military commitments that serve neither the interests of the American people nor the cause of peace and stability in the world. The pursuit of continuous military domination has bogged our foreign policy in strategic quicksand.”

The Washington Post report does not mention whether the Biden administration was able to get the Taliban to agree to an extension of the May 1 deadline, or was blowing past it unilaterally, which could risk renewed attacks by the insurgent group. The Taliban has vowed to keep up its “armed struggle against foreign forces” if foreign forces stay past the agreed-upon date.

A civil war is already raging between the Taliban and the U.S.-backed Afghan government, but U.S. forces in the country have not suffered a single combat casualty since the Doha agreement was signed. That could change if U.S. troops stay unilaterally past the deadline, wrote Quincy Institute’s Adam Weinstein, an Afghanistan combat veteran who has been leading the Quincy Institute’s campaign advocating for complete U.S. withdrawal of forces from Afghanistan, in his recent brief for QI:

Keeping U.S. troops in the country beyond May without a negotiated extension is very likely to lead to the Taliban once again targeting U.S. troops. Regional dialogue inclusive of the Taliban may continue, but bilateral negotiations with the Taliban are unlikely to continue. Restarting these talks will prove difficult, as the Taliban loses trust in the U.S. commitment to leave militarily, and the Afghan government becomes more certain of a continued U.S. presence.

Moreover:

…Even if the Taliban and Afghan government do continue to negotiate after a unilateral extension of U.S. troops, the Biden administration should avoid conditioning a future withdrawal on the outcome of a fragile diplomatic process and a prospective agreement that may never be achieved, much less implemented. 

Upon Tuesday’s news, Weinstein said he was pleased that the administration “has taken a critical step toward ending America’s longest running war,” and reiterated that taking troops out is “imperative to creating the opportunity for peace in the region and is a step forward in adopting a foreign policy rooted in sustainable diplomacy and aid.”

Biden has already publicly stated that it would “be hard to meet the May 1 deadline” but he “can’t picture” U.S. troops staying in Afghanistan past the end of the year. There are currently about 3,500 U.S. troops and 7,000 allied foreign troops in the country.

House Armed Services Committee Chairman Adam Smith (D–Wash.) said last month that the Biden administration was going to delay the May 1 withdrawal for “purely logistical” reasons, but also hinted that Biden wants to explore his options for a long-term U.S. counterterrorism presence on Afghan soil.

The Biden administration has now concluded that any long-term presence is untenable, according to the Tuesday report.

“If we break the May 1st deadline negotiated by the previous administration with no clear plan to exit, we will be back at war with the Taliban, and that was not something President Biden believed was in the national interest,” an unnamed source familiar with deliberations told the Washington Post. “We’re going to zero troops by September.”

September 11 would be a symbolic date, marking the 20th anniversary of the 9/11 terrorist attacks that provoked the U.S. intervention in Afghanistan.

The source added that the United States is “going to remain committed to the [Afghan] government,” but wants to allocate its “blood and treasure” to face other threats, including Russia, North Korea, Iran, and China.

The announcement comes ahead of peace talks between the Taliban and the Afghan government scheduled to begin in Turkey later this week. Both sides have ramped up their military operations ahead of the conference.

U.S. intelligence agencies concluded last year that the Afghan government would fall within two or three years if foreign troops leave before a final peace settlement is reached, according to an assessment leaked last month.

But the Biden administration has signalled that it wants no military role in what comes next for Afghanistan, deal or no deal.

“The President has judged that a conditions based approach, which has been the approach of the past two decades, is a recipe for staying in Afghanistan forever,” a senior Biden administration official told reporters on Tuesday.

Anti-war groups agree, and are commending the president for taking this view and for his reported plan to get out, but caution over any stall-tactics that might be reminiscent of the last decade in which administrations, fearing a political backlash, would not commit to withdrawing troops even when it was clear to most that no military solution would prevail in Afghanistan.

“This decision must just be the beginning, not the end, of a total rethinking of the U.S. approach to conflict. Combat troops must not simply be replaced with different military tactics: covert operations, private contractors, or drone warfare,” warned Stephen Miles, executive director of Win Without War, in a statement Tuesday. 

“The tides are shifting. Now, we must seize on this momentum to end the era of endless war for good.”

UPDATE 4/13 2:15 ET:

Of course the warhawks who want to stay in Afghanistan forever are already unleashing a torrent of doomsday responses:

A full unconditional retreat of U.S. forces from Afghanistan is reckless. If @joebiden is leaving on 9/11 regardless of other considerations, the war is over, the Afghan government will likely fall, & terrorists will enjoy a resurgence threatening America. https://t.co/OZe34wZmh5

— John Bolton (@AmbJohnBolton) April 13, 2021

GOP backlash to Afghanistan decision fierce:@LindseyGrahamSC: “A full withdrawal from Afghanistan is dumber than dirt and devilishly dangerous. President Biden will have, in essence, cancelled an insurance policy against another 9/11.”

— Alex Ward (@AlexWardVox) April 13, 2021

** The story has been updated to reflect new news and statements throughout the day.