Biden Could Have Stopped the Taliban. He Chose Not To.

This article has been updated to reflect news developments.

The Taliban is sweeping across Afghanistan seizing more than a dozen provincial capitals in the past week, and is poised to seize more. Afghan defense forces, finding themselves mostly cut off from U.S. air support, haven’t been able to stop them, and the Afghan government may not survive for much longer. The United States has all but abandoned the country.

A disastrous Taliban takeover wasn’t inevitable. President Biden said his hands were tied to a withdrawal given the awful peace deal negotiated between the Trump administration and the Taliban. But there was still a way to pull out American troops while giving our Afghan partners a better chance to hold the gains we made with them over the last two decades.

Mr. Biden chose otherwise. The way he announced the drawdown and eventual departure of American troops — at the start of the fighting season, on a rapid timeline and sans adequate coordination with the Afghan government — has in part gotten us into the current situation.

Reasonable people can disagree about the wisdom of keeping American military forces in Afghanistan indefinitely, even at very low numbers. I and others have argued that the investment, including the risk to American personnel, is worth it to prevent militant groups from once again overrunning the country.

Mr. Biden believes that further expending U.S. resources in Afghanistan is “a recipe for being there indefinitely.” He rightly notes that President Trump had left him few good options by making a terrible deal with the Taliban. That’s a fine argument, but it explains neither the hastiness nor the consequences we are now observing: the Taliban overrunning swathes of the country, closing in on Kabul, pushing the Afghan security forces and government to the brink of collapse and prompting the Pentagon to prepare for a possible evacuation of the U.S. embassy.

A responsible withdrawal needed more time and better preparation. History will record Mr. Biden, a supposed master of foreign policy for decades, as having failed in this most critical assignment.

As U.S. military planners well know, the Afghan war has a seasonal pattern. The Taliban leadership retreats to bases, largely in Pakistan, every winter and then launches the group’s fighting season campaign in the spring, moving into high gear in the summer after the poppy harvest. At the very least, the United States should have continued to support the Afghans through this period to help them blunt the Taliban’s latest offensive and buy time to plan for a future devoid of American military assistance.

American diplomats could have used this time to negotiate access to regional bases from which to continue counterterrorism operations. Simultaneously, the American military should have prepared contingencies in case those negotiations failed. And even that plan would have meant contending with an increasingly brazen Taliban. (A report by the special inspector general for Afghanistan Reconstruction said the Taliban launched its latest offensive after U.S. and coalition forces officially began drawing down in May.)

Adopting a more judicious approach would have required Mr. Biden to accept two things in addition to a longer timeline: the temporary deployment of additional U.S. forces and the slightly increased risk of American casualties.

Sending additional troops into Afghanistan could have allowed the United States to carry out the withdrawal safely without severely disrupting military support. When the president ordered the pullout, there were some 3,500 U.S. troops in Afghanistan. One thousand or 2,000 additional troops deployed for less than a year could have made a significant difference. They would have allowed Gen. Austin S. Miller, the former U.S. commander in Afghanistan, to continue supporting the Afghan security forces while simultaneously prepping the withdrawal.

Obviously, Mr. Biden did not proceed in this manner. Instead, he ordered a hasty withdrawal of the military just as the Taliban offensive was moving into its major phase.

Several weeks after the president’s announcement, there was no clear plan for responding to terrorist threats emanating from Afghanistan post-withdrawal. It was still unclear if the United States would continue to provide air support to Afghan forces, whether it would have bases in neighboring countries, or how Kabul’s international airport would be secured — an element essential to the maintenance of a U.S. diplomatic presence in the country.

Since then, the U.S. military has provided some support to Afghan forces as the Taliban continues to advance. Unfortunately, this support has been too limited and late to save major cities under attack. In addition, several details of the withdrawal appear to remain unresolved, including how to keep the Afghan military operational without the presence of U.S. contractors for technical support, and how to expedite the immigration of Afghan interpreters who risked their lives for U.S. troops. Protecting these people is an ethical responsibility and strategic imperative, but the administration’s current Special Immigrant Visa Program is plagued by delays.

To be clear, Mr. Trump did put the Biden administration in a bind with a peace deal that specified U.S. troops had to leave by May 1. Still, Mr. Biden blew past that deadline, so pushing for a slightly longer timeline with some extra troops, even if in theory that goes against the peace deal, shouldn’t have been difficult for the administration to accept to permit an orderly, safer withdrawal. The additional financial cost of waiting until early 2022 to complete the retreat would have been bearable with a slightly different budgetary prioritization. (The Senate just approved a trillion dollar infrastructure bill and passed a $3.5 trillion budget plan.)

And then there are the optics of an American retreat. Mr. Biden has repeatedly emphasized the importance of getting U.S. forces out the door, because he was tied to the peace deal and lest U.S. soldiers come under Taliban attack. Is this really the type of fearful, defeatist message a global leader should be sending out to the world?

Both the U.S. and Afghan governments are now scrambling to mitigate the effects of Mr. Biden’s specific decisions. Amid the chaos, there is an important lesson to be learned: Whether announced by tweet or speech, decisions made without concrete plans or robust implementation strategies are wrong — regardless of which president or party spearheads them.

Afghans are paying the price of Mr. Biden’s decision today as the Taliban seizes cities, assassinates officials and begins reimposing its oppressive ideology on a people who have long fought to be free of it.

The United States will likely also continue to pay for its actions in Afghanistan. There’s a real danger that militant groups will reconstitute themselves and once again pose a significant threat to the American homeland. With America’s allies left in the lurch, prospective partners will think twice before offering up their support in future conflicts.

They know that this is not how a global leader acts. And most important, so do we.