Just a couple quick thoughts on the Stevens retirement...
1. Most of this is pretty predictable, no? There will be 25-35 Republicans voting against pretty much whoever Obama puts up (can anyone imagine a 90-10 or 99-0 vote? Don't think so). There are probably over 50 Dems inclined to support whoever Obama puts up. As for the White House, they are presumably well-prepared, and it's pretty obvious that the president prefers make-no-waves solid, mainstream liberal nominees. As a result, liberals will be generally happy with the selection, but there will probably be grumbling that Obama failed to take the opportunity for a truly game-changing selection (which I think is a futile goal; it's impossible to predict the intersection of a potential nominee's thoughts, as guessed at by their history, with whatever issues and internal dynamics the court will have over the next couple of decades). No doubt, the nominee will also raise questions from the left about some area of his or her jurisprudence, but not nearly enough for liberals to oppose the nomination. On the right, there will be a search for controversial statements or views, and if none really exist they will readily be manufactured, from whole cloth if necessary. In other words, expect a close copy of last year's nomination.
2. It is highly unlikely that such a nominee can be defeated. It's always possible, of course, that some scandal will emerge (by the way, I am in favor of careful vetting on these nominations -- this isn't the deputy undersecretary for widgets we're talking about), but barring that, Obama should get this one confirmed.
3. The most interesting vote? Scott Brown, who will now be forced to choose between being a right-wing celebrity and having any hope for reelection. So far, he seems to be trying to straddle that line, but I can't see conservatives forgiving a yes vote here, and while one never wants to place too much emphasis on the effects of one action on voters, a no vote would be a strong indication that he doesn't intend to attempt to remain viable for reelection. (I might as well add that if Crist does jump, I would expect LeMieux to probably vote yes; if Crist is still running in the Republican primary, then LeMieux is a certain no vote).