To some longtime observers of the Supreme Court, the surprising part of yesterday’s oral argument wasn’t that Justice Anthony Kennedy critically questioned the individual mandate; it was the harshly skeptical tone from Justice Antonin Scalia.

Scalia, one of the court’s most outspoken characters, has long been an originalist villain to those on the left, but there was a distinct strain of thought, at least among some constitutional scholars, that he might be inclined to look favorably upon the Affordable Care Act.

That idea rested primarily on his concurrence in Gonzales v. Raich, a 2005 case out of California, in which the court found that the federal government’s power to regulate interstate commerce extended to marijuana that was grown at home solely for personal consumption…