Bombings claim at least 13 lives amid US pullout mess

The career diplomat said that the original US invasion of Afghanistan 20 years ago had "clear objectives". These were capturing those the US believed were behind the Sept 11, 2001, terrorist attacks and ousting a regime that was accused of providing shelter to terrorists.

"They were accomplished really within six weeks. That was enough, we should have left. People were never able to accurately, precisely explain why we were still fighting in Afghanistan," he said. "If you fight a war and you don't know what the purpose of the war is, you're going to fail."

Last February, Freeman pointed out that the "ill-considered" US pacification campaign in that fractious country had failed. "There has been neither clarity nor fixity about our objectives there," he said in a speech at the Watson Institute for International and Public Affairs, where he serves as a senior fellow.

In the interview, Freeman analyzed what he believed was the "going-backward" policy decision process regarding the US Afghanistan move.

Biden made a decision to withdraw US troops in line with the agreement that his predecessor Donald Trump had negotiated, and then he asked the military to plan.

What the military did was plan for force protection, that is, for the safety of the troops as they withdrew.

This is why they closed Bagram Air Base, which would have been essential for the kind of evacuation that is going on now at Hamid Karzai International Airport in Kabul, according to Freeman.

"So first came the decision, then came the planning, and only last came the intelligence assessment. This is all backwards," he said. "So, I think the contingency planning that was done, for the most part, did not focus on the right issue, which is the turmoil."