GWB still has 3 years in office, and the fact is there is very possibly going to be a 3rd nomination to the court by him, if John Paul Stevens retires (doubtful without a Democrat in the White House) or keels over (he's 85, it could happen).
I'm starting to wonder if the reason he nominated Miers is because he knows she's a conservative, though through a self reform movement of her own; he also knows that the left really can't toss many grenades at her, without hitting Harry Reid since she was on his list of acceptable candidates. If they do they've neutered their leader in the Senate, which would be bad. So Miers should have an easy ride though the Senate, except the GOP has their own undies in a bundle over her.
While I'm not happy with her nomination, as I've pointed out before, I'd prefer Rogers-Brown, just maybe George realizes he's getting a third shot, and having a knock down drag out over number 2 wouldn't make that one easier. Could it be possible that she's a also a weapon to be used in a third battle, a "See Harry, I've nominated folks on your list, now get your folks in line" type of thing.