The collapse of the Afghan government has forced the United States into an emergency evacuation operation centered on Kabul’s airport, where thousands of American troops are now securing the final functioning exit route for U.S. citizens, diplomats, allies and Afghans at risk. President Biden said Monday he had authorized roughly 6,000 troops for the mission as the Taliban entered Kabul with a speed that surprised both Washington and the government it had supported for two decades.

The immediate objective is no longer preserving the Afghan state. It is moving people out safely. A contemporaneous USNI account described the mission as a military-assisted noncombatant evacuation operation, with Marines, soldiers and airmen deploying to Hamid Karzai International Airport as the security situation outside deteriorated.

Kabul’s airport becomes the center of U.S. policy

By Tuesday, the Defense Department said the airport was under U.S. control and military flight operations had resumed. An Army report on Pentagon briefings said about 4,000 U.S. troops were on the ground and that commanders hoped to increase evacuation capacity to between 5,000 and 9,000 people per day, with roughly one aircraft departing each hour if operations remained stable.

That capacity is only useful if evacuees can reach the airport. Outside the perimeter, Taliban checkpoints and crowds have complicated movement. The State Department said Tuesday that it had received Taliban assurances of safe passage for civilians, but officials were careful not to treat those promises as sufficient. In an Aug. 17 press briefing, spokesman Ned Price said the United States would judge the Taliban by its actions and continued advising Americans to shelter in place until they received specific instructions to travel to the airport.

The logistical challenge is enormous because the categories of people seeking evacuation overlap but are not identical: private U.S. citizens, embassy personnel, third-country nationals, Special Immigrant Visa applicants, Afghan interpreters and employees, and other Afghans considered vulnerable because of their work or public roles.

The airlift accelerates, but the backlog is large

By Wednesday, the State Department said U.S. military flights had evacuated about 2,000 people in the preceding 24 hours and that more than 4,840 people had been processed for evacuation over several days. Its Aug. 18 briefing said the department was communicating directly with Americans who had enrolled with Embassy Kabul and was preparing to move more Special Immigrant Visa holders.

The Pentagon was simultaneously expanding the military footprint. By Thursday, about 5,200 U.S. troops were at the airport and more gates had been opened, according to a Defense Department update. Officials said more than 2,000 people had been evacuated in the previous 24 hours and emphasized that the central constraint was not aircraft alone but the ability to move people through the airport securely and process them for onward travel.

The evacuation is unfolding under extraordinary time pressure because the United States remains committed to ending the military withdrawal by Aug. 31. That deadline gives commanders and diplomats less than two weeks to complete an operation whose scale is still being determined.

Biden defends the withdrawal but acknowledges the collapse was faster than expected

President Biden publicly defended the decision to leave Afghanistan, arguing that the United States had achieved its original counterterrorism purpose years earlier and could not justify an open-ended military presence to preserve a government unwilling or unable to sustain itself. An Aug. 16 Axios report on his address notes that Biden acknowledged the Taliban takeover unfolded more quickly than his administration had anticipated.

That distinction—between the decision to withdraw and the execution of the withdrawal—is now central to the domestic political debate. Supporters of leaving argue that another military extension would have delayed rather than solved the problem. Critics argue that the collapse of Kabul, the hurried embassy relocation and the scenes at the airport show a failure to prepare for a foreseeable worst-case scenario.

The administration’s immediate challenge is operational rather than rhetorical. Every public defense of the withdrawal is being measured against whether Americans and Afghan partners can actually get through the gates and onto aircraft.

A mission defined by access, security and time

U.S. forces have so far avoided direct conflict with Taliban units around the airport, but the mission remains exposed to multiple risks: crowd surges, checkpoint interference, possible militant attacks and the possibility that aircraft operations could again be disrupted. Stars and Stripes reported that commanders had restored enough order by Tuesday to reopen the airfield after chaotic scenes temporarily halted operations.

The United States is also relying on other countries for transit and temporary housing because the airlift does not end when a plane leaves Kabul. Evacuees must be screened, documented and moved through bases and partner nations before many can continue to the United States.

The scale of the effort is rising each day, but the measure of success will be painfully concrete: how many Americans and eligible Afghans can reach the airport, how many seats can be filled, and whether the system can keep moving before the withdrawal clock expires. The fall of Kabul has ended one phase of America’s longest war. It has immediately begun another operation whose stakes are measured not in territory held, but in people brought out.