As this post gets written, the Pentagon is briefing Joe Biden in the Situation Room, but the situation is obviously disintegrating — much more quickly than the White House anticipated. Despite assurances from John Kirby and others at the Department of Defense, Fox News’ Jacqui Heinrich reports now that the military has already begun its “retrograde” — the final stage of withdrawal from Kabul and the Hamid Karzai International Airport.

First, Heinrich posted the denial:

NEW: US officials are pushing back on reports that evacuation effort may wrap up soon – pointing to flights continuing to depart from Kabul airport

— Jacqui Heinrich (@JacquiHeinrich) August 26, 2021

However, another source told Heinrich that they now suspect “hundreds” of ISIS-K terrorists could be at the airport, and that the military has decided to accelerate its withdrawal. That leaves a virtual “certainty” that Americans will be left behind:

More from this source:

 “Military continues to retrograde and depart airport.  Almost a certainty that Americans will be left behind.  They will have to be extracted after-the-fact through either Taliban negotiation or unconventional means.” https://t.co/P4lofL3ohC pic.twitter.com/EixG7fVMT5

— Jacqui Heinrich (@JacquiHeinrich) August 26, 2021

If this is accurate — and it matches up to reporting from Nick Paton Walsh at CNN even before the attack — this contradicts warnings issued by Joe Biden over the past week. Biden insisted that the Taliban needed to cooperate on withdrawal, and that any attack on US forces would be met with a swift and forceful response. That may still be coming, but if we’re already “retrograding” (retreating, in layman’s language), then it doesn’t appear that Biden’s going to follow through on that threat.

This also looked ominous:

"NATO troops ordered to leave airport gates immediately”… to where? https://t.co/ySZeNohFyf

— Jim Geraghty (@jimgeraghty) August 26, 2021

If NATO troops were ordered away from the gates, it would signal a pullback of the perimeter.  That kind of action under siege has its own kind of momentum. It could mean that the “retrograde” has only hours left instead of days.

So how much of this is solid? It’s hard to tell, but for now, the White House is just saying “we told you so” about the potential for an ISIS-K attack:

"This is not surprising to this White House": President Biden and top administration officials have warned publicly many times about the risks of an attack in Kabul during the last days of the U.S. withdrawal, @edokeefe reports https://t.co/mxRpfPpgkF pic.twitter.com/DULDHrtRtH

— CBS News (@CBSNews) August 26, 2021

CBS News analyst Olivia Gazis points out that the attack undermines the Taliban’s claim to legitimacy. But this discussion also includes claims by Joe Biden (and Donald Trump too) that our departure did not mean that Afghanistan would fall back into a morass of competing terrorist organizations that would eventually target US interests. It didn’t take longer than a few days for that to be proven false:

What does the explosion at the Kabul airport suggest about the potential for a resurgence of terror attacks in Afghanistan? @Olivia_Gazis reports: https://t.co/mxRpfPpgkF pic.twitter.com/FVOv8xFCQ0

— CBS News (@CBSNews) August 26, 2021

As Gazis points out, ISIS-K isn’t a large force in comparison to the Taliban, but is much larger than al-Qaeda was in Afghanistan at the time of the 9/11 attacks. As far as competition with the Taliban, that’s still an open question; it’s much more likely that the radical Islamist ideologies of both groups will eventually create an alliance.

And one has to wonder whether that might have already happened. It’s awfully convenient for the Taliban to claim no responsibility for the attack. That allows them to force the US into an even earlier withdrawal without taking the blame, and betting that Biden will excuse them by claiming his “red line” was only applicable to the Taliban and not ISIS-K. It certainly changes the discussion on deadlines from extensions to curtailing them, right?

Either way, though, it proves that our withdrawal did indeed open the door for terrorist groups to re-establish themselves in Afghanistan, and that our “over the horizon” capabilities can’t even protect the troops we have on the ground at the airport. It’s a disaster on every level, including for those who end up stuck in Afghanistan. Good luck waiting for the “unconventional” ex-filtrations.

Update: Sure looks like the civilian evac phase has come to an abrupt end, with this report from the Washington Post’s Liz Sly:

The Kabul airport attack has nixed hopes of evacuation for the last thousands still hoping to make it out. Am hearing the US military is sealing shut the airport gates. The casualty numbers are growing by the minute. A tragedy piled on a tragedy.

— Liz Sly (@LizSly) August 26, 2021

Military Times reporter hears that they’re welding the gates closed:

Our sources on the ground tell us gates are being welded shut. https://t.co/Fj9u5Up9b4

— Howard Altman (@haltman) August 26, 2021

The “retrograde” must be seriously accelerating at this point.