On The Corner, Andy McCarthy has kindly invited my thoughts on whether today’s 7-2 ruling signals Chief Justice Roberts’s continuing success in forging a more collegial Court and in keeping Justice Kennedy on board. (As Andy points out, Justice Kennedy wrote the 2002 opinion in Ashcroft v. Free Speech Coalition that led to the legislation at issue in today’s case.)

I’m wary of those who profess insights into the internal dealings among the justices, so on the understanding that I’m just speculating, let me offer a couple thoughts:

In today’s case, I’m guessing that the key to getting Kennedy’s vote was that the legislation dealt very carefully with his 2002 opinion, so Kennedy could freely join Justice Scalia’s majority opinion without backtracking on that opinion.

More broadly, if, as seems plausible (and as Jan Crawford Greenburg discussed in this interesting post from a year ago), the Chief Justice and Justice Stevens are frequently competing for Justice Kennedy’s vote, the Chief Justice’s success in that competition might be having the bonus effect of moderating Stevens’s own stances. One possible explanation for Stevens’s several surprising votes this term—in Medellin v. Texas, in Crawford v. Marion County, in Baze v. Rees (I emphasize Stevens’s vote, not his opinion), and in today’s United States v. Williams—is that Stevens is trying to maintain his credibility with Kennedy. In other words, if Roberts generally wins the tug-of-war with Stevens over Kennedy but Stevens is still clinging to Kennedy’s body, Roberts sometimes ends up also dragging Stevens over to his side.