That order did not, of course, emerge. Instead, it took all the king’s horses and all of David Petraeus’s men just to hold Iraq together; a different bad actor, Iran, ended up empowered; and the old problem of repression led to the Arab Spring and the civil wars that followed.

Sticking to the Pax Americana model after these developments would have required keeping American troops in Iraq for decades. It might have forced us to choose between bombing Iran and extending a Cold War-style nuclear umbrella over most of the Arab world. And there still would have been no easy answers about how to deal with corrupt allies, or with the zealots who move in when they fall.

So it’s understandable that the Obama White House has sought a different role. Our withdrawal from Iraq and light-footprint approach to counterterrorism, our strange dance with Bashar al-Assad, our limited intervention against ISIS — they all aim at a more “offshore” approach to the Middle East’s problems. Likewise, the long-sought détente with Iran, which assumes that once the nuclear issue is resolved, Tehran can gradually join Riyadh, Cairo and Tel Aviv in a multipolar order.

But there are two problems.