When asked about reliance on the decisions of foreign courts, Judge Roberts indicated that U.S. courts shouldn't consider themselves bound by foreign precedent. That answer appeals to isolationists on the right, but isn't terribly upsetting to anyone else, since we all know that foreign court decisions aren't binding on U.S. courts. Whether they should be cited (for instance) as reflecting an evolving international standard of decency in death penalty cases is a separate question that Judge Roberts nicely sidestepped.
Here's the result of the Kabuki dance, according to Sen. Biden:
"You have managed to convince Sen. Brownback that you're on his side, and you have managed to convince Sen. Kennedy you're on his side."
And that's exactly what Judge Roberts hoped to accomplish.
How, then, to evaluate Judge Roberts? Prof. Kermit Roosevelt makes the case that "some interesting tidbits have slipped out" which signal that Roberts is "a relatively moderate and restrained judge, not someone who would seek to work radical changes in the Court’s jurisprudence." Unlike judges of the far right, Judge Roberts believes a right to privacy is explicitly protected by the due process guarantee of liberty. He claims to respect precedent (but what judge would say otherwise?), and may therefore be reluctant to vote to overturn Roe v. Wade, although he might also be inclined to allow states to impose onerous restrictions on abortion rights. And he seems to accept the notion that the Constitution is a living document, not a dead thing that must be interpreted as if we all lived in 1789:
It has always been clear that Roberts is not an originalist, but he seemed willing to distance himself emphatically, if implicitly, from Scalia and Thomas. In the course of his discussion of substantive due process, Roberts endorsed the approach of the late Justice [John Marshall?] Harlan (which would align him with Justice David Souter on the current Court) and stated, “I agree that the tradition of liberty is a living thing, yes.”
Still, the best we can say is that Chief Justice Roberts would not likely be worse, and might possibly be a bit better, than Chief Justice Rehnquist. But that, at best, is a guess. As Biden said, we're rolling the dice with Roberts.
Judge Roberts has offered little reason for Democrats to vote in his favor, but there is also little reason to squander political resources on a filibuster that would more appropriately be mounted against an extremely conservative nominee for the moderately conservative Justice O'Connor's seat -- which, as suggested here, is what might be coming next.
Update: Howard Dean has this to say about Roberts' confirmation.