Yeah, I'm starting to see this as a bigger Obama victory than I had previously thought. Romney's the guy who could do well against him, but with the Republicans trying their damnedest to avoid nominating him, he's going to go into the general election pretty lame. If it had just become a Romney vs. Perry fight, it'd have been ugly, but people would be rallying behind him right now. Instead, he'll get the anti-Obama vote, which will be strong, but very little support of his own.
Hey, I'm a liberal registered Democrat, but let me tell you something: Obama is not going to "crush" anyone. He's got a very difficult re-election campaign ahead of him. I think he has a decent chance of winning, and I want him to win because I don't want any more right-wingers appointed to the SCOTUS, but the facts are pretty clear.....this election is going to be a close call.
The only two justices who might come up for replacement are Ginsburg and Kennedy. I think Kennedy's got quite a lot of judging left in him, and Ginsburg will probably retire after this term. Looking back, supreme court justices like to retire when their side is in office. Souter retired when their was a Republican to replace him*. Same thing with O'connor. She was quite clear that she wanted to retire under a Republican president (which might actually have been a factor in Bush v. Gore). If it looks like Obama might not get reelected, you'll see Ginsburg hang it up. If he's a shoe in, as I suspect he will be, she might tough it out a bit longer, but health's going to force her out pretty soon. Either way, she won't be around for another term if it means retiring under a GOP president.
*Despite their hatred of him, Souter remained a die-hard republican. He was just an old-school type, rather than the right-wing whack job that the GOP seems to crave, nowadays.