The fact is both Trump and Biden were committed to leave Afghanistan. Had Trump won a 2nd term, he would have been facing the same constraints that Biden did. The US failed to appreciate how quickly the Afghan government and military would fold. And when that become apparent, the US was in no position to respond. Neither leader was going to send in 5-10 thousand US troops back to Afghanistan to secure our exit. It simply was not politically feasible after so many years of lost American lives.
President Biden had committed to ending the war in Afghanistan, but when he came into office he was confronted with difficult realities left to him by the Trump Administration. President Biden asked his military leaders about the options he faced, including the ramifications of further delaying the deadline of May 1. He pressed his intelligence professionals on whether it was feasible to keep 2,500 troops in Afghanistan and both defend them against a renewed Taliban onslaught and maintain a degree of stability in the country. The assessment from those intelligence professionals was that the United States would need to send more American troops into harm’s way to ensure our troops could defend themselves and to stop the stalemate from getting worse. As Secretary Austin testified on September 28, 2021, “If you stayed [in Afghanistan] at a force posture of 2,500, certainly you’d be in a fight with the Taliban, and you’d have to reinforce yourself.” Chairman Milley testified on September 29, 2021, “There’s a reasonable prospect we would have to increase forces past 2,500, given the Taliban very likely was going to start attacking us.” There were no signs that more time, more funds, or more Americans at risk in Afghanistan would have yielded a fundamentally different trajectory. Indeed, the speed with which the Taliban took over the country showed why maintaining 2,500 troops would not have sustained a stable and peaceful Afghanistan.