John Mearsheimer and Steven Walt offer up the best argument out there on why the U.S. shouldn't attack Iraq in the latest Foreign Policy. [C'mon, let's get to the full disclosure--ed. Mearsheimer is a senior colleague of mine here at Chicago; Walt used to be]. Essentially, it's that Saddam Hussein can be deterred, and can therefore be contained. They marshall some strong evidence to support their case. But:

1) Using the fact that Saddam Hussein only initiated two wars in the past twenty years as evidence that he's not a serial aggressor is like arguing that pre-1945 Germany was not inherently hostile because they only triggered two world wars. War's an esceptionally rare event in world politics, and the fact that Hussein triggered two of the last three inter-state conflicts in the Middle East is not a point in his favor.

2) Assume that Hussein can be deterred -- is deterrence really as stable an outcome as Mearsheimer and Walt posit? The status quo in the Middle East has been a slow erosion of the U.S. position and a rise in Anti-Americanism. A lot of this is based on the Israeli-Palestinian conflict, but a lot is also predicated on the U.S. being the prime movers behind the sanctioning of Iraq, combined with the presence of U.S. forces in Saudi Arabia.

I said last fall that the best reason to invade Iraq is to remove the need for large-scale U.S. forces to be based in Saudi Arabia, which has destabilized that country for the worse. I've found that this argument plays very well with much of the anti-war crowd, but they don't believe that the Bush administration is really thinking that way. However, Fred Kaplan's latest "War Stories" piece in Slate suggests otherwise. The key graf:

Though few officials speak of it, even off the record, there is a train of thought, in certain quarters of the Pentagon and the State Department, that large numbers of U.S. soldiers should not remain based in Saudi Arabia for much longer. Our military presence provides a handy target for terrorists (rhetorically, if not physically) and aligns us too tightly with a corrupt kingdom from which we might wisely begin to seek distance. However, it would be unsafe and unsettling, for the entire region, to pull out of Saudi Arabia while Saddam Hussein is still in power. Saddam must go so that we can go. This may be the best rationale for "regime change" in Iraq, although, for obvious reasons, you will never hear any official articulate it. This rationale also marks Iraq as a unique case, which therefore allows North Korea to be considered as a unique case as well.

[Is that the only reason you like Kaplan's piece?--ed. Well, I also like the fact that he's echoing what I said back in October. Advantage: Drezner!!]