WASHINGTON — Afghan government forces are collapsing even faster than U.S. military leaders thought possible just a few months ago when President Joe Biden ordered a full withdrawal. But there’s little appetite at the White House, the Pentagon or among the American public for trying to stop the rout and it probably is too late to do so.

Biden has made clear he has no intention of reversing the decision he made last spring, even as the outcome seems to point toward a Taliban takeover. With most U.S. troops now gone and the Taliban accelerating their battlefield gains, American military leaders are not pressing him to change his mind. They know that the only significant option would be for the president to restart the war he already decided to end.

The Taliban, who ruled the country from 1996 until U.S. forces invaded after the 9/11 attacks, captured three more provincial capitals Wednesday and another on Thursday, the 10th the insurgents have taken in a weeklong sweep that has given them effective control of about two-thirds of the country. The insurgents have no air force and are outnumbered by U.S.-trained Afghan defense forces, but they have captured territory with stunning speed.

Biden Says U.S. Troops Have Done Enough the Past 20 Years

John Kirby, the chief Pentagon spokesman, said the Afghans still have time to save themselves from final defeat.

“No potential outcome has to be inevitable, including the fall of Kabul,” Kirby told reporters. “It doesn’t have to be that way. It really depends on what kind of political and military leadership the Afghans can muster to turn this around.”

Biden made a similar point a day earlier, telling reporters that U.S. troops had done all they could over the past 20 years to assist the Afghans.

“They’ve got to fight for themselves, fight for their nation,” he said.

The United States continues to support the Afghan military with limited airstrikes, but those have not made a strategic difference thus far and are scheduled to end when the U.S. formally ends its role in the war on Aug. 31. Biden could continue airstrikes beyond that date, but given his firm stance on ending the war, that seems unlikely.

“My suspicion, my strong suspicion, is that the 31st of August timeline’s going to hold,” said Carter Malkasian, who advised U.S. military leaders in Afghanistan and Washington.

Officials Push for Planning of Potential Evacuation of Personnel

Senior U.S. military officials had cautioned Biden that a full U.S. withdrawal could lead to a Taliban takeover, but the president decided in April that continuing the war was a waste. He said Tuesday that his decision holds, even amid talk that the Taliban could soon be within reach of Kabul, threatening the security of U.S. and other foreign diplomats.

The most recent American military assessment, taking into account the Taliban’s latest gains, says Kabul could be under insurgent pressure by September and that the country could fall entirely to Taliban control within a couple of months, according to a defense official who discussed the internal analysis Wednesday on condition of anonymity.

Officials said that there has been no decision or order for an evacuation of American diplomatic personnel from Afghanistan. But one official said it is now time for serious conversations about whether the U.S. military should begin to move assets into the region to be ready in case the State Department calls for a sudden evacuation.

Kirby declined to discuss any evacuation planning, but one congressional official said a recent National Security Council meeting had discussed preliminary planning for a potential evacuation of the U.S. Embassy but came to no conclusions.

Any such plan would involve identifying U.S. troops, aircraft and other assets that may have to operate from within Afghanistan or nearby areas. The U.S. already has warships in the region, including the USS Ronald Reagan aircraft carrier and the USS Iwo Jima amphibious ready group with the 24th Marine Expeditionary Unit aboard.

Afghan Military Will Have Hard Time Holding Off Through End of Year

Military officials watching the deteriorating situation said that so far the Taliban hasn’t taken steps to threaten Kabul. But it isn’t clear if the Taliban will wait until it has gained control of the bulk of the country before attempting to seize the capital.

Military commanders have long warned that it would be a significant challenge for the Afghan military to hold off the Taliban through the end of the year. In early May, shortly after Biden announced his withdrawal decision, Gen. Mark Milley, chairman of the Joint Chiefs of Staff, said he foresaw “some really dramatic, bad possible outcomes” in a worst-case scenario. He held out hope that the government would unify and hold off the Taliban, and said the outcome could clarify by the end of the summer.

The security of the U.S. diplomatic corps has been talked about for months, even before the Taliban’s battlefield blitz. The military has long had various planning options for evacuating personnel from Afghanistan. Those options would largely be determined by the White House and the State Department.

American Forces May Have to Fight Their Way Out

A key component of the options would be whether the U.S. military would have unfettered access to the Kabul international airport, allowing personnel to be flown systematically out of the capital. In a grimmer environment, American forces might have to fight their way in and out if the Taliban have infiltrated the city.

The U.S. also would have to determine who would be evacuated: just American embassy personnel and the U.S. military, or also other embassies, American citizens, and Afghans who worked with the U.S. In that last category are former interpreters and those who face retaliation from the Taliban. The U.S. has already started pulling out hundreds of those Afghans who assisted troops during the war.

Senior defense leaders have been talking and meeting daily, laying out their grim assessments of the security situation in Afghanistan. Officials pointed to the fall of Baghlan Province as a worrisome bellwether, because it provides the Taliban with a base and route to Kabul from the north.