Comparing lessons from exiting Afghanistan with Vietnam exit

For more on the evacuation operation in Kabul and the challenges the U.S. military faces in light of Thursday's attacks, Amna Nawaz turns to retired Col. Mark Cancian. He had a 38-year career in the Marine Corps and was involved in the evacuation of Saigon in the early 1970s. He's now a senior advisor at the Center for Strategic and International Studies, a Washington, D.C. think tank.