What Afghanistan shows is that we need a new definition of expertise, one that relies more on proven track records and healthy cognitive habits, and less on credentials and the narrow forms of knowledge that are too often rewarded. In an era of populism and declining trust in institutions, such a project is necessary to put expertise on a stronger footing.

It’s true that many experts also opposed the Afghanistan War and thought that the United States was seeking unrealistic goals. But individuals with the most subject-matter expertise often tended to get things the most wrong. This included generals with experience in counterinsurgency in Iraq and Afghanistan as well as many think tank analysts with the most focus and interest in those conflicts.

Perhaps we shouldn’t be surprised. Philip Tetlock, a psychologist, has famously shown that subject-matter experts are no better at accurately forecasting geopolitical events relevant to their field than those with training in different areas. Similarly, in a different study, the intelligence community, with access to classified information, proved less accurate than an algorithm weighted toward the views of amateurs with no security clearances but a history of making accurate forecasts.