I haven’t heard (or seen) any discussion of this, but suppose Amy Coney Barrett becomes a Supreme Court justice, as I expect she will. That makes six conservatives and three progressives (for lack of better labels).
The rule in the Supreme Court is that if the Chief Justice is in the majority, he or she gets to designate the author of the opinion. The Chief Justice can write every majority opinion if he or she wants, and can certainly take the most important cases.
Suppose a case comes along with a 5-3 lineup (not counting Roberts). You’ve got Alito, Thomas, Gorsuch, Kavanaugh, and Barrett on one side and the three progressives (Breyer, Sotomayor, and Kagan) on the other.
Roberts might want to join the progressives, but what would that avail? He would be on the losing side, one of four dissenters. His dissenting opinion would be a cry in the dark. If he joins the five conservatives, however, he gets to write the majority opinion, and that’s a big deal. He can frame the issue as narrowly as he wants (to limit its precedential value) and lay whatever legal foundation he wants under it.
I think we’ll see a lot of 6-3 cases in the next few years. Roberts will be in the majority not because he wants to be there, but because he wants to trim the sails of the conservatives (especially Alito and Thomas, and maybe also Barrett).
