When confronted with two potential nuclear powers, (Iran and Iraq) the United States government can't be belligerent enough- many expect Iran to be a target for "regime change" when and if the Iraqi adventure ends.
When confronted with another nuclear power (North Korea), this time pretty much confirmed, Bush can't bend backwards enough to assure both the North Koreans and (inevitably) the Chinese that things will be solved peacefully. Oh, and let's not forget the Chinese's human rights record makes Saddam look like Jefferson. And they've got nukes.
Suspicious observers will ask what the difference is. Some would say oil. Some would say Islam. Some would say geostrategy. All may be true, but all miss the point: the difference is the difference between having nukes, and wanting nukes. Want them, and you're a target. Obtain them, and you're untouchable.
This is not going to do the cause of anti-proliferation much good.