And he writes no opinion expressing that opinion. The case is Wednesday’s Rosemond v. United States, an interesting decision about the mental state required for aiding and abetting under federal criminal law — straight out of your first-year Criminal Law class, if you’ve taken one. In the process, the majority (Elena Kagan, whose writing style I’ve come to very much enjoy, joined by Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor, John Roberts, Anthony Kennedy, and largely Antonin Scalia) has these two footnotes:
 Some authorities suggest an exception to the general rule when another crime is the “natural and probable consequence” of the crime the defendant intended to abet. See, e.g., 2 LaFave §13.3(b), at 356 (citing cases); but see id., §13.3 (“Under the better view, one is not an accomplice to a crime merely because … that crime was a natural and probable consequence of another offense as to which he is an accomplice”). That question is not implicated here, because no one contends that a §924(c) violation is a natural and probable consequence of simple drug trafficking. We therefore express no view on the issue.
 We did not deal in these cases, nor do we here, with defendants who incidentally facilitate a criminal venture rather than actively participate in it. A hypothetical case is the owner of a gun store who sells a firearm to a criminal, knowing but not caring how the gun will be used. We express no view about what sort of facts, if any, would suffice to show that such a third party has the intent necessary to be convicted of aiding and abetting.
Court-watchers are familiar, of course, with Scalia’s general opposition to the use of legislative history as a guide to interpreting statutes, and to his tendency to join all of a majority opinion except the parts (often the footnotes) that mention legislative history. But this is the first time that I’ve noticed Scalia refuse to join footnotes that have nothing to do with legislative history, and that simply express no opinion on an issue. I take it that Scalia has strong feelings on the underlying questions (perhaps he thinks they are so well-settled that even ostensibly “expressing no opinion” wrongly suggests that they are contested), but I haven’t followed his substantive criminal law views enough to know the details. If anyone can shed more light on this, I’d be much obliged.