By Kelly Werthmann

(CBS4)– The Pentagon announced Monday that the last U.S. troops had left Afghanistan, ending America’s longest war. Withdrawing troops, however, did not come easily.

(credit: CBS)

“Any withdrawal of this nature – and this is already the largest air evac in U.S. history – is going to be complicated,” Greg Young, a political science and international affairs professor at CU Boulder, said. “Unfortunately, tragedies have arisen.”

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Young also served 24 years with the U.S. Navy. He said, while the withdrawal from the two-decades-long war has not been great and “we could’ve done better,” it is time to leave.

“The idea that we’d continue to sacrifice young American men and women to continue a 20-year occupation that hasn’t really altered the culture of the Taliban one iota in those 20 years,” he told CBS4’s Kelly Werthmann, “that’s not a mission for the United States military.”

With that said, Young also acknowledged there are veterans who served in Afghanistan who disagree with the move to leave now.

(credit: CBS)

“Young military men are going to feel betrayed,” Young said. “Afghans are going to feel betrayed. That doesn’t mean we give up on our interests in Afghanistan [like to protect women’s rights and promote women’s education], but it is, to me, not a military mission.”

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With the U.S. now out, the Taliban has effectively taken control of Afghanistan. Whether or not they can be trusted remains to be seen, but at this point, Young said it is not a vital national security interest for the United States anymore.

“Should the Taliban provide sanctuary to another group in violation to the agreement with the Trump administration, we have a right to go back in,” Young explained. “Maybe not stay for 20 years but deny any sanctuary for Al Qaeda or ISIS-like groups.”

Over the last couple of weeks, CBS4 has interviewed and shared stories of Afghan Americans living in Colorado who are desperately trying to get their families out of Afghanistan. One young man told CBS4 on Monday he wants to get his parents to safety, but said “I really lost my hope…now that the U.S. is leaving.”

(credit: CBS)

President Biden said he would address Americans on Tuesday about the decision not to extend the U.S. mission past the deadline, even though some Americans and at-risk Afghans were unable to evacuate.

“For now, I will report that it was the unanimous recommendation of the Joint Chiefs and of all of our commanders on the ground to end our airlift mission as planned,” Biden said in a statement Monday afternoon. “Their view was that ending our military mission was the best way to protect the lives of our troops, and secure the prospects of civilian departures for those who want to leave Afghanistan in the weeks and months ahead.”

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The withdrawal came nearly 20 years after the U.S. military first entered Afghanistan after the terrorist attacks on Sept. 11, 2001.

Kelly Werthmann