Barack Obama’s analogies for the Islamic State have come a long way in the last couple of years. In a January 2014 interview with The New Yorker, the president infamously likened ISIS, the ascendant al-Qaeda affiliate that had just taken over the Iraqi city of Fallujah, to a “jayvee” basketball team.

“The analogy we use around here sometimes, and I think is accurate, is if a jayvee team puts on Lakers uniforms that doesn’t make them Kobe Bryant,” Obama told David Remnick.

But that was at a time when Obama’s advisers were describing ISIS as a “flash in the pan,” according to my colleague Jeffrey Goldberg’s new cover story on the president’s foreign policy. Obama’s evaluation of ISIS shifted, Jeff reports, once the group seized the Iraqi city of Mosul in the spring of 2014.

And somewhere along the way, ISIS evolved, in the president’s mind, from a jayvee squad to the Joker. Jeff has more on the analogy Obama began using to explain why ISIS posed a direct threat to the United States—and why defeating the group should be an urgent U.S. priority:

Advisers recall that Obama would cite a pivotal moment in The Dark Knight, the 2008 Batman movie, to help explain not only how he understood the role of ISIS, but how he understood the larger ecosystem in which it grew. “There’s a scene in the beginning in which the gang leaders of Gotham are meeting,” the president would say. “These are men who had the city divided up. They were thugs, but there was a kind of order. Everyone had his turf. And then the Joker comes in and lights the whole city on fire. ISIL is the Joker. It has the capacity to set the whole region on fire. That’s why we have to fight it.”

It’s a fascinating characterization of both ISIS and the pre-Arab Spring, pre-Syrian Civil War Middle East, made all the more fascinating when you go back and watch The Dark Knight with ISIS on your mind (Batman fans and Middle East experts: Let me know what you make of the analogy at hello@theatlantic.com).

Consider this scene, where the Joker (the inimitable Heath Ledger) crashes a meeting of Gotham’s mob bosses after stealing their money:

The tragically underestimated, seemingly crazed Joker upends business as usual, cowing some gang leaders by sadistically slamming one guy’s head into a pencil, making outsized demands of his rivals, threatening to blow up the joint, and calling for those assembled to unite around a common enemy: Batman. Sound vaguely familiar?

Even with this dark view of ISIS, Obama is eager, in his interviews with Jeff, to place the challenge posed by the Islamic State in perspective. “ISIS is not an existential threat to the United States. Climate change is a potential existential threat to the entire world if we don’t do something about it,” Obama said. You heard it here first, folks: Climate change is clearly the Penguin. Or something.