Chief Justice John Roberts, however, wrote a majority opinion on behalf of himself and the four more liberal members of the Court that split the difference between these positions while upholding the law. The Chief Justice agreed with the Court's conservatives that the mandate to purchase health insurance was beyond Congress's power under the Commerce Clause; however, he also agreed with the Court's liberals that the mandate could be sustained under Congress's power to collect taxes since the penalty for failing to purchase health insurance could be considered a tax rather than a fine. This latter conclusion was sufficient to sustain the mandate and other related provisions of the law. (In a separate analysis, Roberts led a majority of 7 justices in concluding that the ACA's Medicaid provisions are unconstitutionally coercive and that states may therefore opt out of expanding Medicad coverage without losing any existing Medicaid funds.)
In addition to the obvious and critical questions about the implications of the decision for health care in the United States and the interesting puzzle of how it might influence the upcoming presidential election, the decision reflects important challenges for scholars of law and judicial politics.
First, I should point out that the decision in the case was---in the one most important respect---contrary to my own expectations. I had predicted a 5-4 decision striking down the mandate under the Commerce Clause. Though the Court ruled exactly as I predicted on that issue, the five justice majority resurrected the the tax argument on behalf of the law after every appeals court that had heard challenges to the law had rejected it. I certainly did not predict that. Though a handful of people predicted that Roberts would join a narrow majority to save the mandate (Adam Serwer and Will Wilkinson spring to mind, but there were undoubtedly others. Also, Ann Coulter's 2005 take on John Roberts is worth a looksee.), no one I know of predicted that the case would hinge on Roberts's reading of the tax clause.
Law professors who argued from legal doctrine made the worst predictions about the outcome of the case. Laurence Tribe's analysis of the case and his prediction that the law would be upheld 8-1 under the Commerce Clause are especially comical in retrospect. Political scientists, as a group, did much better, but still missed the boat. Attitudinalists like me typically assumed Kennedy was the mostly likely member of the Court's conservative majority to side with the liberals against the mandate. Mike Bailey and Forrest Maltzman's forecast---based on a statistical model accounting for both justices' preferences and the weight of precedent---of a 6-3 decision in favor of the mandate under the Commerce Clause hinged on a Kennedy defection and Roberts going along to control the opinion. Though this law-and-politics forecast got the direction of the decision right, it did not predict the composition of the majority or the holding on the Commerce Clause issue.
As I look back now on what I wrote about the Supreme Court last February when I predicted a 5-4 decision against the mandate and hold it up against the decision itself and news reports that Chief Justice Roberts initially sided with the Court's other conservatives in voting to strike down the entire law before switching sides and crafting an opinion that broke for the ACA while still holding against it on the moot Commerce Clause issue, I can't help but think (self-servingly) that I was generally right about what makes the Court tick but (obviously) wrong in one important detail: John Roberts took the threat to the Supreme Court's legitimacy that would come from the backlash against a decision striking the law more seriously than I.
In particular, I see these three things going on the decision.
1. The "law" doesn't matter much in Supreme Court decisions. Despite the legal academy's nearly complete consensus that the Court's prior Commerce Clause cases left the action-inaction distinction raised by opponents of the ACA's individual mandate utterly insupportable, a majority of the Court held that Congress could not directly compel commerce as part of a regulatory scheme. Despite the fact that the ACA does not refer to the penalty on failing to purchase health insurance as a tax, the repeated public insistences of President Obama and other supporters of the law that the uninsured were not going to be taxed, and the failure of any lower federal court to decide for the ACA under the power to tax, the Court held that the mandate is constitutional since the penalty may be considered a tax. As I see it, the decision looks like it does because John Roberts wanted to decide for the mandate but did not want to publicly surrender the principal that Congress could do anything it pleased. These are political judgments, not legal ones, and the law---understood as precedent or the language of the statute---was ultimately no constraint on what the Court did or did not do.
2. External constraints matter. I had written that public opinion was so evenly divided on the ACA question that the Court could decide the case however it wanted without facing a realistic threat to its standing. My hunch is that John Roberts saw a public that was deeply divided on health care reform, a president and party willing to actively campaign against the Court for the first time since FDR, and a news media willing to back a court-curbing movement to the hilt, and he backed down. I think the Court could have weathered the storm, but John Roberts, of course, has much more reason to be risk averse on this count than I do. After all, history has been quite kind to John Marshall's wily assertion of judicial independence amidst total political surrender. Perhaps John Roberts hopes to pull off a similar trick.
3. The Chief Justice is different. I am working on a project that makes the claim that the Chief Justice plays a unique role in protecting the legitimacy of the Supreme Court. My coauthor, Carla Flink, and I write:
[There is a] general...relationship between the leadership capacity of the chief justice and the quality of the Supreme Court’s decisions in terms of their prospects for supporting the legitimacy of the Court... Synthesizing this intuition with on a model of public management due to Meier and O’Toole (1999), we articulate a theory of the chief justice’s role on the United States Supreme Court. In particular, theories of public administration tend to emphasize the effects of management on the quality of outcomes produced by an institution rather than by its ability to produce outcomes consistent with a particular political ideology or by a particular process. This approach suggests that the leadership of the Supreme Court, embodied formally in the office of the chief justice, has a special interest in producing outcomes of high quality for his institution rather than merely producing outcomes consistent with his personal policy preferences or legal philosophy. Unlike prior theoretical accounts of the chief justice’s role in Supreme Court decision-making, we do not view the chief as a merely a justice of ordinary motivation (perhaps political) with some extra-ordinary institutional prerogatives (e.g. the ability to assign opinion authorship when voting with a conference majority). Instead, we consider the chief justice as a “manager” who exerts leadership on his institution to improve the quality of its outputs in terms of the standing of the institution itself.The upshot is that the Chief Justice's office is different than that of the Associate Justices. In particular, the Chief has special responsibilities to protect and enhance the legitimacy of the Court as an institution. If John Roberts acted to preserve the standing of the Court, then his behavior is entirely consistent with this approach (even if it might not have been necessary in this case).