WASHINGTON — As President Biden signaled this week that he would let a May 1 deadline pass without withdrawing American troops from Afghanistan, some officials are using an intelligence assessment to argue for prolonging the military mission there.
American intelligence agencies have told the Biden administration that if U.S. troops leave before a power-sharing settlement is reached between the Taliban and the Afghan government, the country could fall largely under the control of the Taliban within two or three years after the withdrawal of international forces. That could potentially open the door for Al Qaeda to rebuild its strength within the country, according to American officials.
The classified assessment, first prepared last year for the Trump administration but not previously disclosed, is the latest in a series of grim predictions of Afghanistan’s future that intelligence analysts have delivered throughout the two-decade-long war.
But the intelligence has landed in a changed political environment. While President Donald J. Trump pushed for a withdrawal of all forces even before the terms of the peace deal required it, Mr. Biden has been more cautious, saying Thursday that he does not view May 1 as a deadline he must meet, although he also said he “could not picture” troops being in the country next year.
The decision looms as one of the most critical of Mr. Biden’s young presidency. He long argued while vice president for a minimal presence in Afghanistan, but has been said to have privately described as haunting the possibility of allowing the country to descend into collapse.
Some senior Biden administration officials have expressed skepticism of any intelligence prediction of a resurgence of a weakened Al Qaeda or of the Islamic State. Taliban commanders remain opposed to the Islamic State in Afghanistan, and Al Qaeda, which has little current presence in the country, could regroup instead in any number of other lawless regions around the world.
Also left unanswered by the intelligence warning is the question of whether Afghanistan could really prosper if American troops remain indefinitely. Their presence would most likely prevent a collapse of the nation’s own security forces and allow the government in Kabul, the Afghan capital, to retain control of its major cities, but the Taliban are still likely to gradually expand their power in other parts of the country, including curbing the rights of women.
A Taliban spokesman said on Friday that the group was committed to last year’s peace agreement “and wants the American side to also remain firmly committed.” If troops are not withdrawn by May 1, the spokesman promised, the Taliban would “continue its jihad and armed struggle against foreign forces.”
Biden administration officials insisted no final decision had been made. Nevertheless, with the deadline looming, administration officials are jockeying to influence Mr. Biden and his top national security officials. While Lloyd J. Austin III, the secretary of defense, has not signaled what course of action he prefers, some Pentagon officials who believe American forces should stay longer have pointed to the intelligence assessment predicting a Taliban takeover of the country.
Some military commanders and administration officials have argued that any set date for withdrawing the approximately 3,500 American troops who remain, whether it is May 1 or at the end of the year, will doom the mission. The only way to preserve hard-fought gains in Afghanistan, they said, is to keep the small American presence there long enough to force a lasting deal between the Taliban and Afghan government.
These officials have used the intelligence assessment to make the point that a withdrawal this year will lead to a fall of the current government, a sharp erosion of women’s rights and the return of international terrorist groups. A rush to the exit, some officials said, will only drag the United States back into Afghanistan soon after leaving — much as was the case in Iraq in 2014, three years after the Obama administration pulled troops out of that conflict.
The White House has held a series of meetings on Afghanistan, and more are to come. On Thursday, the president said he was waiting for briefings from Mr. Austin, who met recently with Afghan officials, and Secretary of State Antony J. Blinken, who conferred this week with NATO allies, for their bottom-line advice on what he should do.
For many Biden administration officials, the issue that has resonated the most clearly is the threat that a Taliban takeover could pose to Afghan women. While some former intelligence officials predict the Taliban will initially take care not to roll back women’s rights altogether — at least in major cities — if they take over the entire country, it will be difficult to guarantee protections for women, such as education for girls and access to health care.
“Any agreement must preserve their gains if Afghanistan wants to ensure the international community’s continued political and financial support,” Linda Thomas-Greenfield, the U.S. ambassador to the United Nations, told the Security Council this week. “We will not give an inch on this point.”
The Biden administration is making a final effort before May 1 to show progress in slow-moving negotiations between the Taliban and the Afghan government in Doha, Qatar. The Taliban, according to American officials, are stalling.
The administration is pushing the two sides to participate in a peace conference in Turkey to demonstrate progress. Simultaneously, the American and Taliban negotiators continue to try to cement a 90-day reduction in violence, but so far, both sides have hesitated to agree.
The classified intelligence assessment of the Taliban largely taking control assumes that the Afghan government and the Taliban fail to reach a political agreement and that a civil war would erupt after the American exit.
Administration officials warned that making any intelligence estimate is challenging, that predictions about the future are always imprecise and that various factors influence the analysis.
For example, intelligence estimates depend on whether international funding for the Afghan government remains in place. The more money the United States and its allies provide Afghanistan, the longer the government in Kabul should be able to retain control of some of the country. But some officials said that history shows that once American troops are withdrawn, Congress moves quickly to cut financial support for partner forces.
There is also a debate in Washington about the seriousness of the threat of a return of terrorist groups. For now, the number of Qaeda and Islamic State militants in Afghanistan is very small, a senior U.S. official said.
Some senior lawmakers with access to the classified assessments said that it was not certain that if the United States withdrew that Al Qaeda could rebuild a base in Afghanistan from which to carry out terrorist attacks against the United States.
“What is that threat really going to be?” Representative Adam Smith, Democrat of Washington State and the chairman of the House Armed Services Committee, said this week during a virtual conference on Afghanistan. “This isn’t the 1990s when Al Qaeda set up camps, and they had the Taliban and no one was paying attention to them.”
Mr. Smith said keeping U.S. troops in Afghanistan actually increased the risk to Americans there, incurred greater financial costs and handed a propaganda victory and recruiting tool to the United States’ enemies.
Some counterterrorism officials believe that Al Qaeda would prefer to re-establish its headquarters in Afghanistan, should American troops withdraw. But other officials said Al Qaeda’s leadership might be just as likely to look to Africa or the Middle East.
While American intelligence officials have been mostly focused on the threat of Al Qaeda, senior military officials have also raised the prospect of a growth in the power of the Afghanistan arm of the Islamic State.
But in recent years, the Taliban have been at odds with the Islamic State. The two groups have fought, and the Taliban have for the most part pushed back Islamic State forces.
“I can’t imagine a scenario where ISIS and the Taliban would strategically cooperate or collaborate in Afghanistan,” said Lisa Maddox, a former C.I.A. analyst. “The Taliban is an ideological organization, and that ideology is Afghan-centric and not aligned with ISIS’ overarching goals.”
The intelligence estimate predicted that the Taliban would relatively swiftly expand their control over Afghanistan, suggesting that the Afghan security forces remain fragile despite years of training by the American military and billions of dollars in U.S. funding.
Offensives last year in Kandahar and Helmand Provinces, two areas in the country’s south where the Taliban have long held sway, demonstrated that the police and local forces are unable to hold ground, prompting elite commando forces and regular army troops to take their place — a tactic that is likely unsustainable in the long run.
The Afghan security forces still rely heavily on U.S. air support to hold territory, which American military leaders acknowledged this week. It is unclear whether that American air power would continue if U.S. forces left Afghanistan, perhaps launched from bases in the Persian Gulf, although the Pentagon has drawn up such options for the White House.
“The capabilities that the U.S. provides for the Afghans to be able to combat the Taliban and other threats that reside in Afghanistan are critical to their success,” Gen. Richard D. Clarke, the head of Special Operations Command, told the Senate on Thursday.
Julian E. Barnes and Eric Schmitt reported from Washington, and Thomas Gibbons-Neff from Kabul, Afghanistan. Najim Rahim contributed reporting from Kabul.