Julie Saltman points out that, despite all the complaints by the right, Alberto Gonzales probably wouldn't make for a "moderate" Supreme Court justice, or anything resembling a future David Souter. That's true enough, although I doubt Gonzales' undying "loyalty to the president" matters much here. Supreme Court justices are obviously free to be independent, and at any rate, I doubt that George W. Bush himself cares much, personally, for banning contraception or overturning Roe v. Wade (although both he and Gonzales appear happy to allow so many restrictions on abortion as to make the "rights" virtually meaningless). So I doubt any future justice would be receiving marching orders to placate the religious right.
The other thing to note is that from everything we know about Gonzales, he's someone who shifts with the wind, and isn't particularly principled in any way. That's not a good thing when it comes time to craft, say, memos allowing the torture of detainees. On the Supreme Court, though, it could meanand it's always hard to predict, but let's grasp at strawsthat Gonzales would move with prevailing public sentiment, as the average Supreme Court justice tends to do; and that public sentiment has steadily become more liberal over the years, at least in social issues, and should continue to trend in that direction. (Young people, after all, are far more liberal on abortion and gay marriage than the generation before them.) The same goes, perhaps, for some economic issues, although the prevailing public sentiment here is markedly less progressive.
I don't think anyone should be under any illusion that Gonzales would be a very conservative Justice: friendly to business, placing undue burdens on a woman's right to choose, infringing on privacy, rendering affirmative action meaningless, chipping away at Congress' ability to regulate commerce, etc. etc. The complaints by the religious right about him are, to a large degree, ingenuous. Personally, I think Gonzales has shown enough disrespect for the rule of law that he does not deserve a Supreme Court appointment, now or ever. But what he does not appear to be, however, is a bull-headed, hell-or-high-water conservative like Antonin Scalia, who would stand athwart history and yell 'Stop!'. In many ways, that could make a difference.