The reversals in Afghanistan are confounding for a Biden national security team that has rarely known personal failure: Jake Sullivan, the national security adviser, went to Yale, Oxford and Yale Law School. Antony Blinken, secretary of state, attended Harvard and Columbia Law.

These are America’s best and brightest, who came to the messy endgame of the Afghanistan war with spotless résumés. That’s one of the parallels to the Vietnam War, where a similar group of brilliant policymakers who had rarely experienced failure was confounded by an obdurate enemy from another century. The U.S. foreign policy establishment of the 1960s hit a wall with Vietnam and never fully recovered. We’ll see what happens with the Biden team.

The sudden collapse of the Afghan government and the nightmare at Kabul airport stunned senior officials. They knew that the situation was fragile, and intelligence analysts had predicted that the government of President Ashraf Ghani would likely fall soon. But one sign that the CIA didn’t foresee an imminent collapse was that Director William J. Burns was traveling in the Middle East last week on a six-day trip and didn’t return until Sunday, the day Kabul fell, just a day before he had planned.