U.S. forces have been deployed to Afghanistan for nearly 20 years since the Taliban government was toppled in the aftermath of the Sept. 11, 2001, terrorist attacks on the United States.

Now, America’s longest war is about to come to an end. The U.S. military has vacated its most significant airfield in Afghanistan — reportedly without full coordination with Afghan counterparts — a sign that the Pentagon plans to finish its withdrawal within days.

Earlier this year, the Biden administration committed to withdrawing all U.S. troops from Afghanistan by Sept. 11. But the process has been faster than anticipated, and nearly all troops are now expected to depart in the coming days.

Here are key questions about the conflict and the efforts to resolve it, answered.

Why is the United States in Afghanistan?

U.S. forces intervened in Afghanistan in October 2001, unleashing airstrikes that helped Afghan resistance forces oust the Taliban government, which had harbored the al-Qaeda militants involved in planning the 9/11 attacks.

While the Taliban was driven from power in the capital, Kabul, on Nov. 13, 2001, the group retained support in rural areas and gradually began regaining strength and seizing territory.

After nearly 20 years of conflict, the Taliban is the strongest it has been since 2001 .

Many Afghans fear that the Taliban will one day return to power in Kabul. Under Taliban rule, militants enforced hard-line interpretations of sharia law and essentially barred women from public life.

What is at stake as withdrawal looms?

U.S.-led NATO forces withdrew from combat operations at the end of 2014, although NATO troops remained on the ground. The resulting vacuum was widely seen as allowing the Taliban to push back against Afghan security forces and gain territory. U.S. officials have historically wanted to keep troops in Afghanistan for that very reason, fearing that withdrawal could allow militants to use the country once again to stage attacks on the United States.

As the United States has reduced the scale of its operations, an emboldened Taliban has escalated its attacks on key provincial capitals and is now believed to control roughly a third of the country.

A recent U.S. intelligence assessment warned that the Afghan government could fall within six months of a U.S. military departure. Worst-case scenarios could include chaotic civil war, Army Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, said last month.

Civilians have repeatedly expressed concerns that when U.S. troops pull out, regular Afghans will pay the price and be left at the mercy of the Taliban, which still aspires to establish a hard-line Islamist government in Kabul.

How many U.S. troops are in the country?

In January, the Trump administration shrank the official number of troops in Afghanistan to 2,500 — the lowest level since 2001. (The figure fluctuates, and about 1,000 more than that were on the ground in mid-April.) Lawmakers on both sides of the aisle opposed that change, saying that it wasn’t clear there would be enough human resources for effective counterterrorism operations and that the reduction in troops may not have been consistent with the terms of the United States’ agreement with the Taliban.

While those numbers have been drastically reduced since the Biden administration announced its withdrawal plans, anywhere from 650 to 1,000 troops are expected to remain in the country to guard the U.S. Embassy and the airport.

What is the situation on the ground?

Violence has ramped up across the country in recent months, and the Taliban’s increased dominance has led to the rise of anti-Taliban militias and sparked fears of intensified civil war.

Taliban attacks have continued to target civilians, and the group increasingly has carried out targeted killings and assassinations. At least 11 journalists and media workers were killed in the country last year.

In recent years, other armed groups, including an Islamic State offshoot, have taken advantage of the chaotic conflict to pursue their own agendas. The Islamic State claimed responsibility for some of the deadliest attacks on civilians in the capital in recent years, often targeting the minority Hazara population in west Kabul.

What is the status of the peace talks between the Taliban and Afghanistan’s government?

Peace talks between the Afghan government and the Taliban began in September after a lengthy delay following a February 2020 agreement by the United States to withdraw troops. With Washington playing a key role in the peace process, Biden’s win in the November presidential election contributed to further delays, some analysts suspect, as parties expected potential changes to U.S. policy.

Since then, Afghanistan’s political elite has been deeply divided over a path forward. Abdullah Abdullah, a top Afghan official who leads the High Council for National Reconciliation, told CNN on Wednesday that the parties have made “very little progress” and that the talks were proceeding at a “very slow pace.”

Some have warned that the lack of consensus among Afghan leaders could allow the Taliban to present a more unified front and thus gain greater leverage. Afghan civilians opposed to the Taliban worry that if the group secures a role in a power-sharing government, it could eventually take over the government in Kabul and return to the harsh rule it imposed before its removal from power in 2001.

Afghan officials have also expressed fears over the complete withdrawal of U.S. troops without a solid political settlement in place.

How has the withdrawal gone so far?

By July 6, more than two months head of the final deadline, U.S. Central Command said that it had completed more than 90 percent of the withdrawal process.

U.S. forces have handed over seven facilities to the Afghan Defense Ministry, including Bagram Airfield, what had been the United States’ most important airfield in Afghanistan.

U.S. officials said the handover of Bagram went smoothly following weeks of planning. But Afghan officials on the ground said they were caught by surprise by the sudden departure.

Darwish Raufi, the Bagram district governor, told The Washington Post he was frustrated to be excluded from the process. The U.S. military left “without coordinating with security and defense forces and in general without coordinating” with the Afghan government and Bagram district officials, he said in a statement.

“Some looters went in. Some of them were arrested, and some others escaped,” Raufi added. “They were in for equipment that they could carry.”

In the meantime, the Taliban has continued to capture more territory. In recent days, over 1,000 Afghan soldiers have fled into neighboring Tajikistan to seek safety from the advancing insurgents.

This report has been updated.

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