“The administration is presenting the choices in a way that is, at best, incomplete,” said Meghan O’Sullivan, a deputy national security adviser under President George W. Bush who oversaw earlier stages of the Afghan war. “No one I knew was advocating the return of tens of thousands of Americans into ‘open combat’ with the Taliban.”

Instead, some, including the current military leadership of Defense Secretary Lloyd J. Austin III and Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff, asserted that keeping a relatively modest force of as few as 3,000 to 4,500 troops along with the extensive use of drones and close air support could have enabled Afghan security forces to continue holding off the Taliban without putting Americans at much risk.

“There was an alternative that could have prevented further erosion and likely enabled us to roll back some of the Taliban gains in recent years,” said Gen. David H. Petraeus, the retired commander of American forces in Afghanistan and former C.I.A. director who argued the mission was making progress while serving alongside Mr. Biden under President Barack Obama.