I'm not sure what invitation he has in mind. In most of the court's major rulings, Roberts drove pretty hard to Kennedy's right, including in the school race case, writing opinions that didn't beckon to the court's supposed swing man. In other cases, of course, like the decision to uphold the federal "partial-birth" abortion law, the two were in sync. In 13 of the court's 19 cases that split 5-4 along ideological lines, Kennedy and Roberts were together on the winning side, as Linda Greenhouse at the New York Times has pointed out. (Four of the remaining six involved Texas death-penalty law.) It's true that in the ruling that struck down federal campaign-finance reform, Kennedy wanted to go further than Roberts. But that's one example.
Let's say, though, that next term, Roberts is even more successful in wooing Kennedy than he was this term, which seems entirely plausible. What kind of "unity" would that get us? The answer is in Sunstein's new essay (here's an early version). He argues that 1) today's court has no William Brennan or Thurgood Marshall (Ruth Bader Ginsburg is not that liberal), whereas the 1980 court had no Antonin Scalia or Clarence Thomas; 2) three of the court's supposed "liberals"—Breyer, David Souter, and John Paul Stevens—are really moderates, akin to the old Stevens-Lewis Powell-Byron White trio; and 3) the trade-off in the center of Harry Blackmun for Anthony Kennedy is a loser for the left, too. Sunstein still believes in restraint (he calls his version of it "minimalism"). But while he doesn't think the likes of Brennan and Marshall should run the show, he also now says that "something has gone badly wrong if the Court has a strong right-wing without any real left." And it's even worse that the court's moderates are being cast as left-wingers, thus belying the court's overall conservative creep.
Sunstein's framework shows that if Kennedy joins with Roberts more often to "unify" the Roberts court, the court only will move farther to the right. Maybe Kennedy would temper the reasoning of some conservative victories. But they'd still be just that—wins for the court's conservative bloc, which is far more conservative than it was a quarter-century ago. Is that really what the left should be hoping for?
I hope Rosen is right and I've judged the Roberts court prematurely. I hope the court becomes so amicable and accommodating that Breyer and Souter and Stevens and Ruth Bader Ginsburg can sign on to majority opinions regularly and without reservation. Peace and love for everyone! But Breyer, Ginsburg, Souter, and Stevens—the moderates who actually work with John Roberts—don't seem sanguine about that possibility. These justices joined each other's often-angry dissents this term more than is customary, to give them more force. They read those dissents from the bench, a gesture that signifies intense disapproval, if not despair. John Roberts, his colleagues seem to have concluded, has the courage of his convictions. It's just that those convictions aren't about unity and restraint. They're about moving constitutional law to the right, as President Bush chose him to do.