Chief Justice Roberts has said he likes mystery novels; once, as a lower-court judge, he invoked Sherlock Holmes’s “dog that didn’t bark.” But at the King v. Burwell arguments, Roberts himself was in effect the dog that didn’t bark, saying far less than expected and thus leaving reporters to puzzle over the mystery of how he might vote.

But the one question he did ask about statutory interpretation does merit particular notice, as the Washington Post’s Robert Barnes notes. It pertains to “Chevron deference” — the doctrine under which the Court generally should defer to an agency’s reasonable interpretation of an ambiguously worded statute.