I want to plug this interview with Graham Allison, nuke-worrier extraordinaire, done by one of my former colleagues. Allison makes exactly the right point: nuclear weapons are "really the only existential threat to America". Unfortunately I haven't read his book yet, so I don't know what he recommends to do about Iran and North Korea. I've suggested before (as others have) that we might not be able to stop Iran from going nuclear, and we might have to learn to live with that—in particular, by creating a defense alliance among the Gulf States to contain Iran.

I'm not so sure that's the right strategy anymore. One of the things the U.S. has tried to do in the Middle East over the past 20 years is to create a balance of power in the Middle East. First Iraq would be our counterweight to Iran. Then Saudi Arabia was a counterweight to Iraq. Then Turkey was a counterweight to Iran. Now Iraq again. etc. Sometimes it proves useful—the State Department played India and Pakistan off each other masterfully in 2002 to secure Pakistan's cooperation.

But in the long term, it's unstable. We've created a region that looks very much like Europe, circa 1914, and no one seems to realize it. Iranian leaders—and here I mean both hardliners and Khatami-line moderates—certainly worry about threats from the United States, but they worry just as much about Sunni radicalism from Saudi Arabia, a hegemonic Iraq, and the rise of Pakistan. Unless we do something to defuse that state of affairs—and creating a Gulf State deterrent certainly isn't that—states will always have reason to pursue nukes.