Why Go Nuclear?

As I've been shaking in my boots (OK, I don't wear boots, but you know what I mean) waiting for the Senate Republicans to drop the nuclear bomb on the filibustering of judicial nominees, I've suddenly taken to wondering why they're bothering. It seems like a move that will get them a lot of negative press and provide Democrats with a 2006 campaign issue, all just so they can shoehorn 8-10 more radical Bush nominees through the confirmation process. I have a hard time imagining they couldn't as easily line up an alternative slate of conservative candidates with equally appalling views and authoritarian aims who wouldn't have the damaging paper trail and disreputable baggage. Of course as I write this I recognize the "pre-emptive" element here; by changing the law they would not only get to ram the backlog through, but also be given more leeway to choose even more hideous nominees. In any event, it seems risky. A good Democrat could take advantage of this.