Joe Biden was facing the biggest crisis of his presidency on Monday after the stunning fall of Afghanistan to the Taliban caught his administration flat-footed and raised fears of a humanitarian catastrophe.

Recriminations were under way in Washington over the chaotic retreat from Kabul, which one Biden opponent described as “the embarrassment of a superpower laid low”.

Bowing to pressure, officials said the president would leave his country retreat, Camp David, to address the nation from the White House on Monday afternoon.

The Taliban swept into Kabul on Sunday after President Ashraf Ghani fled the country, ending two decades of a failed experiment to import western-style liberal democracy. Diplomatic staff were flown to safety but thousands of Afghans who worked with US forces were stranded and at risk of deadly reprisals.

As harrowing scenes played out on television – including desperate Afghans clinging to a US transport plane before takeoff – the White House scrambled to explain how the government collapsed so quickly.

Last month Biden, pointing to the Afghan military’s superior numbers and technology, predicted: “The likelihood there’s going to be the Taliban overrunning everything and owning the whole country is highly unlikely.”

Unrepentant, the president issued a statement on Saturday, insisting the sudden withdrawal had been the only possible choice.

But the response by Biden, who ran for election promising unrivalled foreign policy credentials after 36 years in the Senate and eight as Barack Obama’s vice-president, was jarring to many. A headline in the Washington Post read: “Defiant and defensive, a president known for empathy takes a cold-eyed approach to Afghanistan debacle.”

The botched withdrawal and the Taliban’s lightning offensive also threw a political gift to Republicans. Many drew comparisons to the humiliating departure of US forces from Saigon in Vietnam in 1975.

Biden’s predecessor, Donald Trump, said: “What Joe Biden has done with Afghanistan is legendary. It will go down as one of the greatest defeats in American history!”

Mitch McConnell, the Republican leader in the Senate, described it as “a shameful failure of American leadership” and warned that “the likelihood that al-Qaida will return to plot attacks from Afghanistan is growing”.

He added: “A proud superpower has been reduced to hoping the Taliban will not interfere with our efforts to flee Afghanistan. God knows what fate awaits vulnerable Afghans who cannot make it to Kabul to board one of the final flights out. Terrorists and major competitors like China are watching the embarrassment of a superpower laid low.”

But such criticism was undercut by the fact that Trump struck a deal with the Taliban last year, seeking to pull forces out even earlier and even to invite the militants to Camp David while snubbing the Afghan government. Democrats accused Trump and his allies of trying to “rewrite history”.

Liz Cheney, a Republican member of the House armed services committee, acknowledged to CBS: “In the Trump administration the agreement that was negotiated, Secretary [of state Mike] Pompeo negotiated, actually was a surrender agreement … We never should have done that, but President Biden never should have withdrawn forces.”

Ben Sasse, a Republican senator for Nebraska and fellow Trump critic, wrote in the National Review: “The sad thing is, many in my party are trying to blame-shift as if the last administration didn’t set us on this course. Here’s the ugly truth: neither party is serious about foreign policy … President Trump pioneered the strategy of retreat President Biden is pursuing, to disastrous effect.”

Sasse joined some commentators in arguing that America had achieved a stalemate preferable to the current disaster. But others suggested Biden’s only options were to withdraw or escalate in a no-win situation.

Chris Murphy of Connecticut, a Democratic member of the Senate foreign relations committee, said: “Our 20-year, trillion-plus-dollar nation-building campaign, crippled by design flaws, cannot continue. I know this is hard for the foreign policy establishment in Washington to accept, but staying another year or five years or 10 years wouldn’t have changed that.

“At the very least, I hope this tragedy allows US policymakers and military leaders to finally learn a lesson about the hubris of sending our military to far-off places to try and build modern armies and democratic governments in our mould.”

Polls have long shown strong public support for ending America’s longest war. Images of atrocities and refugees might shift some opinions, although foreign policy rarely proves decisive at the ballot box. Afghanistan has received comparatively little media coverage over the past two decades.

Gil Barndollar, a senior fellow at Defense Priorities and a veteran who deployed to Afghanistan twice, told reporters: “I hate to be a cynic here but I suspect that for most Americans, with maybe the partial exception of those of us who served there, it is going to be forgotten pretty quickly.

“We never cared that much in the first place, even at the height of this, when we had a hundred thousand troops there; a lot of Americans weren’t really aware of that. So I suspect this is going to be largely water under the bridge fairly quickly, as dispiriting as that is as a citizen of the republic.”

Benjamin Friedman, policy director at Defense Priorities, said: “It’s a Beltway thing to be very focused on what’s happening in Afghanistan. It makes sense given the dramatic events there but I don’t think that there’s evidence that the American public is deeply mortified by this or that it will hurt Biden politically.

“Maybe I’m wrong, but it remains the case that the American public remains overwhelmingly in support of the US withdrawal from Afghanistan and withdrawal, therefore, will be beneficial politically to Biden, slightly … people tend to overestimate how long our memories are for events.”

Such views echoed a tweet by Ruben Gallego, an Iraq war veteran and Democratic congressman, who posted: “I haven’t gotten one constituent call about [Afghanistan] and my district has a large veteran population.”