"Our exit from Afghanistan was a disaster..."Top U.S. military leaders faced blistering questions in the Senate Tuesday about the chaotic withdrawal of troops from Afghanistan and the swift takeover of the Taliban.Defense Secretary Lloyd Austin said the Afghan army's sudden collapse caught the Pentagon off-guard as he acknowledged miscalculations in America's longest war including corruption and damaged morale among the Afghan ranks."The fact that the Afghan army that we and our partners trained simply melted away – in many cases without firing a shot – took us all by surprise… It would be dishonest to claim otherwise.”President Joe Biden has faced the biggest crisis of his presidency over the dramatic end to the war in Afghanistan, raising questions about his judgment and foreign policy expertise.Army General Mark Milley, chairman of the Joint Chiefs of Staff, appeared to agree under questioning that the episode “damaged” America’s credibility. “I think that damaged is one word that could be used, yes."He noted that the U.S. military had warned since late 2020 that an accelerated withdrawal - without being tied to any conditions - could precipitate the collapse of the Afghan military and government.Milley and General Frank McKenzie both testified that they had believed it would have been best to keep a minimum of 2,500 troops in the country.But Milley also said that by August of 2021 it became clear that staying meant fighting the Taliban."The risk to mission, the risk to force, and most importantly, the risk to the American citizens remaining, that was going to go up, not down, on the first of September."While Republicans in the committee blamed President Biden for the messy pullout, Democrats and military leaders stressed the withdrawal didn’t happen overnight.SENATOR ELIZABETH WARREN: "Anyone who says the last few months were a failure but everything before that was great clearly haven't been paying attention."Secretary Austin admitted the exit wasn’t perfect, but praised American personnel who helped airlift 124,000 Afghans out of the country, an operation that also cost the lives of 13 U.S. troops and scores of Afghans in a suicide bombing outside the Kabul airport.