What’s behind Roberts’ surprising decision?

Say this for the lead opinion in the health care case the Supreme Court handed down Thursday: nobody saw that coming. Chief Justice Roberts joins with the court’s more liberal wing to uphold the Affordable Care Act … as a tax? The result is, to put it mildly, counterintuitive. Scribes have been busily dissecting the chief justice’s doctrinal analysis from the instant the opinion went viral, but here’s a different thought: doctrine may not be the key to this judgment. As Leo Strauss once made a point of telling his students, a text can be read in many different ways, and will mean different things depending on the lens with which one reads it. The text the chief justice published on Thursday may or may not make good sense read as constitutional doctrine. But read it as constitutional politics and things get more interesting.

Not politics in the way the Washington punditry means, of course. Roberts’ opinion has nothing to do with helping or hurting President Obama’s re-election chances this fall. The truth is, Supreme Court justices are rarely interested in that sort of thing. They see themselves as above partisan allegiances and the grand questions of law they decide as more important than run-of-the-mill partisan disputes.

No, I mean politics in the constitutional sense, concerning the Supreme Court’s role in the Constitution’s structure. The danger this case held for the court from the beginning was the possibility — indeed, high likelihood — that it would draw the institution into an acute confrontation with the executive branch in the middle of an election year, and at the same time force the justices into the thick of a policy debate where they have no genuine expertise. The chief justice’s opinion can be fruitfully read as a sort of maneuver, an effort to avoid these evils while simultaneously blocking the federal government’s attempted power grab.

Consider: Roberts begins with the Commerce Clause question, where the Obama administration placed nearly all the weight of its argument. According to the administration, the Commerce Clause permits Congress to regulate any behavior (or non-behavior) that has some incidental effect on commerce. Roberts rejects that contention root and branch. Indeed, for the first time in the Supreme Court’s modern Commerce Clause jurisprudence, he announces a clear and decisive limit to what the federal government may do with its commerce authority: it may regulate only actual economic activity, and then only if the activity has a substantial effect on interstate commerce. It may not regulate a person’s choice not to enter the stream of commerce in the first place.

Had this been the sum and substance of the opinion, liberals would have bewailed it as the constitutional apocalypse they feared. But of course it is not the end; Roberts goes on to the administration’s secondary argument. Yet by placing the Commerce Clause discussion where he does, by holding unequivocally that the individual mandate cannot survive on commerce grounds, Roberts makes the Commerce Clause holding necessary to the final judgment. That means the limits on the commerce authority he announced (and with which the four dissenting justices agree) will control in future cases.

This is a significant, even major, development, but one that is largely concealed by the opinion’s ultimate judgment. Yet even that judgment turns out to be rather less a victory for the government than it first seems.