[Hoot Gibson]

As Joe Biden vacations at Camp David...

Afghanistan's collapse: Did US intelligence get it wrong?

American intelligence sources say they correctly predicted the fall of Kabul.

As panicked Afghans watched Taliban fighters roll into the capital city of Kabul Sunday, sealing the collapse of the U.S.-backed government there, many Americans were left wondering how top Biden officials could have been so wrong in their recent proclamations that Kabul would not easily fall.

Just days ago, a U.S. military analysis reported by ABC News predicted that Kabul could fall within 90 days -- not by the weekend.

"This is a crisis of untold proportions," Rep. Jackie Speier (D-Calif.) told NBC News Sunday as Taliban militants swept into Kabul. "This is an intelligence failure. We underestimated the Taliban and overestimated the resolve of the Afghan Army."

But numerous U.S. officials tell ABC News that the opposite was true, insisting that key intelligence assessments had consistently informed policymakers that the Taliban could overwhelm the country and take the capital within weeks -- essentially repeating the 1975 fall of Saigon, when helicopters hastily evacuated diplomats from the U.S. embassy's rooftop as the North Vietnamese Army stormed into the South Vietnam capital.

The Taliban, which has long called itself the "Islamic Emirate of Afghanistan," announced they had entered Kabul soon after Afghan President Ashraf Ghani fled the country on Sunday afternoon, setting off a rush to the city's airport and a stepped-up evacuation of the U.S. embassy by a fleet of military helicopters guarded by AH-64 Apache attack helicopters orbiting the once-impenetrable Green Zone. President Joe Biden rushed to move in thousands of U.S. troops to evacuate American officials still in the capital.