WASHINGTON — US Defence Secretary Lloyd Austin told Congress on Tuesday (Sept 28) that the Afghan army's sudden collapse caught the Pentagon "by surprise," as military leaders confronted a contentious Senate hearing about how and why America lost its longest war.

Republican lawmakers accused President Joe Biden of lying about recommendations from his military that some troops should be kept in Afghanistan. Even Mr Biden's Democrats expressed frustration with a chaotic withdrawal that left US troops dead and American citizens behind.

Mr Biden's approval ratings have been badly damaged by last month's spectacular collapse of the two-decade war effort, with painful images of Afghans clinging desperately to a US military plane as they tried to escape Taliban rule.

Thirteen US troops also died in an Aug. 26 suicide bombing trying to safeguard the evacuation effort that, ultimately, relied on support from the militant Islamist Taliban, a long-time US foe.

General Mark Milley, chairman of the Joint Chiefs of Staff, and General Frank McKenzie of US Central Command also acknowledged being caught off-guard by the speed of the Taliban takeover and collapse of the US-backed government in Kabul.

It was their first public congressional testimony since the Taliban won the war in August.

"The fact that the Afghan army we and our partners trained simply melted away – in many cases without firing a shot – took us all by surprise," Mr Austin, a former four-star general who served in Afghanistan, told the Senate Armed Services Committee.

"It would be dishonest to claim otherwise."

Mr McKenzie and Mr Milley testified that they had believed it would have been best to keep a minimum of 2,500 troops in the country. In an August interview, Mr Biden denied his commanders had recommended that, saying: "No. No one said that to me that I can recall."

Republican Senator Joni Ernst said Mr Biden's decision to keep former President Donald Trump's unconditional withdrawal agreement with the Taliban had squandered US sacrifices for what he thought would be "a cheap political victory."

"The loss of our service members, and abandonment of Americans and Afghan allies last month was an unforced, disgraceful humiliation that didn't have to happen," Ms Ernst said.

Senator James Inhofe, the panel's top Republican, described it as a "horror of the president's own making."

White House spokesperson Jen Psaki said Biden's military experts had provided "a range of viewpoints" about Afghanistan, and that Mr Biden believed leaving troops there would "mean war with the Taliban."

Mr Milley, the top US military officer, noted military warnings since late 2020 that an accelerated, unconditional withdrawal could precipitate the collapse of the Afghan military and government.

"That was a year ago. My assessment remained consistent throughout," Mr Milley said.

'WHY DON'T YOU RESIGN?'

Republican Senator Tom Cotton asked Mr Milley why, if everything he said was true, he didn't resign his position.

Mr Milley pushed back strongly, saying a US president does not have to agree with the advice of his generals. "This country doesn't want generals figuring out what orders we are going to accept and do or not. That's not our job," Mr Milley said.

Mr Austin, Mr Milley and senators — many of whom oversaw the war effort for years — seemed full of questions about what went wrong, citing failures to appreciate the impact of corruption and damaged morale in the ranks.

"There's a series of strategic lessons to be learned," Mr Milley said.

Democrats faulted Republicans for blaming Mr Biden, who has been president since January, for everything that went wrong during the 20 years US troops have been in Afghanistan, including under Mr Trump.

"Anyone who says the last few months were a failure, but everything before that was great, clearly hasn't been paying attention," Democratic Senator Elizabeth Warren said.

Much of the hearing was devoted to Republicans' questions about Mr Milley's interviews with Mr Bob Woodward and other reporters for books on the chaotic last months the former president was in the White House.

Mr Austin praised US personnel who helped airlift 124,000 people out of the country.

But Mr Milley acknowledged that while the evacuation effort was a logistical accomplishment, the withdrawal was a "strategic defeat" that left the Taliban back in power.

He warned the Taliban "remains a terrorist organization" which has not broken ties with al Qaeda.

A reconstituted al Qaeda in Afghanistan with aspirations to attack the United States was "a very real possibility" — perhaps in as little as a year, he said.

That warning is likely to unsettle lawmakers, who are skeptical of the Pentagon's ability to quickly respond to al Qaeda and Islamic State threats.

Mr Austin defended plans to address future counterterrorism threats from overseas after a botched drone strike killed 10 Afghan civilians last month.

"Over-the-horizon operations are difficult but absolutely possible. And the intelligence that supports them comes from a variety of sources, not just U.S. boots on the ground," Mr Austin said. REUTERS