I don't think it's a matter of lower priority, but rather who is going to handle it. North Korea is under Chinas thumb, if China so chooses. Pressure is being put on China to make North Korea knock it off. China is being put in a position of either saying, "we're not going to make them" (in effect declaring support), or "we can't make them" (in effect giving us rhetorical authority to deal with N Korea ourselves).
What if, S.Korea, Japan, TAIWAN, and others went nuclear in about a weeks worth of American shipments to them. China would be mortified. They wouldn't even have time to bitch. We would say, you had your chance, you blew it. Their economy would tank, and pressure could come from all sides. If China believes they can bluff Dubya into folding, I got some land to sell ya. I think they know by now who they are messin with. They just don't want to jump in too soon, but they will, they almost have to. If I were Dubya, I would be discusing nukes with Taiwan pretty soon. Oh my, nuke talks leaked to the press.....Pshaw! China would come unglued. The've been waiting for years for an opening to be able to get Taiwan back without a war. Definatly not with nukes in Taiwan.
The Dems want Bush to fret over N. Korea because they know it a tougher nut to crack than the middle east dictators. I believe he's doin the right thing. If they get hungry, let China or the UN feed them, been there,done that. They've proved they are liars and we should treat them as such. No treaty unless it is verifiable.