"We began to engage in nation-building operations and maybe some of that was necessary in a narrower sense to protect our interests but the broader things we did probably ultimately in the long term didn't help us. They diffused our efforts," McKenzie told NBC News on Friday.
"I don't know that Afghanistan is governable or sustainable with a Western model. I know that Afghanistan is governable and sustainable from an Afghan model. But we paid too little attention to Afghan realities on the ground," he said.
McKenzie said that overlooking the Afghan reality was costly and was a "hubris on our part, and on the international community."
He went on to say that he was "proud of" American men and women on the ground on the day of the controversial withdrawal from Afghanistan, when Afghans died trying to hold on to the plane. He said that the fact it was a highly politicized event was "regrettable."
McKenzie admitted that getting Afghan allies out of the country is a very "slow" process but did not promise anything on that "moral obligation."
The top general agreed that Afghanistan was a bipartisan failure for four US administrations in two decades and added that it was a combination of "military and diplomatic failures."
Stressing that the war-torn country is still a breeding ground for threats to the US, he said it is still too early to say what is going to happen in Afghanistan. Extremist groups protected by the Taliban will pose new dangers for future US leadership, he said.
The US declared the completion of the Afghanistan pullout Aug, 30, 2021, ending the 20-year war.
Pakistan was right
He said the Taliban always had a haven in Pakistan and the US was never able to resolve that in the two decades of the conflict or come to an agreement with Pakistan on the issue.
The reason was because the "Pakistanis never believed that we would stay, always thought that we would leave," he said, adding, “You know that? They were right, we left."