Forget it -- the Democrats won't mount a successful fight over Samuel Alito. Three reasons:
(1) He's regarded as highly qualified.
(2) He was confirmed unanimously in 1990 when Bush the Elder appointed him to the federal appeals court.
(3) He's being touted as a "nice guy" (or so a liberal attorney on NPR just said a few minutes ago).
That's all it going to take -- this guy is going to make it.
If Bush had picked, say, Edith Jones, who denounced Roe from the bench in no uncertain terms, there might be a fight. But the gist of Alito's dissent in Planned Parenthood v. Casey was about spousal notification. It would be silly to think that he's any less anti-abortion than Jones -- but what will be said about Alito and abortion is that he has supported one particular restriction on abortion. This isn't enough to rally big numbers of ordinary voters. Liberals aren't like the NRA -- we don't all immediately conclude that all abortion rights are in jeopardy whenever one aspect of abortion rights is threatened; we can't successfully rally the faithful under those circumstances. So forget it -- it's over.