From the 2004 Illinois Senate debate:
MODERATOR: Let's talk about some of the decisions that might have to be made. There may not be any weapons of mass destruction in Iraq, but there are such weapons in Iran, there are such weapons in North Korea. Ambassador Keyes, how strongly would you consider preemptive action against those nations?
KEYES: Well, all such decisions--and that's what I thought was one of the brilliant things about the Iraq decision--is that you go after those things that are most susceptible to the right kinds of action. Iraq was susceptible to direct military action, and so the President acted. If you're talking about North Korea, you have to look at the entire context in which we deal with the North Korean threat. And that includes relationships with the Chinese and the possibility that you're talking about something that could escalate into a larger war. We also have mechanisms preexisting for bringing international pressure to bear on both the North Koreans and the Iranians, when it comes to proliferation of weapons of mass destruction, particularly nuclear weapons.
This basically falls into the "suck on this" school of foreign policy advocated by Tom Friedman.