Brendan Hoffman for The New York Times  Chief Justice John G. Roberts Jr. and the rest of the Supreme Court are scheduled to start hearing arguments on March 26.  The decision in the case, expected by June, will have practical consequences for tens of millions of Americans without health insurance, and it may affect Mr. Obama’s re-election chances.  It will also shape, if not define, the chief justice’s legacy.  Chief Justice Roberts is just 57, and he will probably lead the Supreme Court for an additional two decades or more. But clashes like the one over the health care law come around only a few times in a century, and he may well complete his service without encountering another case posing such fundamental questions about the structure of American government.  The case will require the chief justice to choose between two competing instincts.  On the one hand, he views himself as a steward of the court’s prestige and authority, and he has called for incremental decisions from large majorities rather than broad but sharply divided rulings. “As chief justice, Roberts has been extremely careful with the institutional reputation of the court,” said Barry Friedman, a law professor at New York University who has filed a brief urging the court to uphold the law.  The court has not rejected legislation as ambitious as the health care law since the 1930s. There is, moreover, only one plausible way for the justices to strike down the law, scholars who study the court say: by a 5-to-4 vote divided along ideological lines.  All of that might augur a cautious approach.  At the same time, Chief Justice Roberts has embraced an array of assertive judicial projects that have interpreted the Constitution in ways that have fundamentally reshaped American law. The court he has led since 2005 has cut back on campaign spending limits, gun control laws, procedural protections for criminal defendants and the government’s ability to take account of race in decisions about employment and education.  Chief Justice Roberts has not exhibited the same intense focus on the question of federal power that is at the heart of the health care case, and he has offered only passing hints about his thinking on the subject. He did surprise some in 2010 by signing, along with the court’s four more liberal members, Justice Stephen G. Breyer’s majority opinion affirming Congressional power to authorize the continued civil confinement of sex offenders after they have served their criminal sentences.  That ruling led some observers to say that Chief Justice Roberts is not as interested in exploring the limits of federal power as were Chief Justice William H. Rehnquist, who died in 2005, and Justice Sandra Day O’Connor, who retired in 2006.  “Federalism has less salience with this court than it did with the Rehnquist court,” Sri Srinivasan, then a lawyer in private practice, said at a Chamber of Commerce briefing in 2010. Mr. Srinivasan is now principal deputy solicitor general.  Predicting the outcome of the health care case is hard, because it is both surpassingly important and quite idiosyncratic.  The law, Patient Protection and Affordable Care Act, sets out to eliminate the United States’ status as the only rich country without almost universal health care. Mr. Obama’s aides compare its significance to that of Medicare or Social Security, while Republican leaders say it helps move the country dangerously close to European-style big government.  The court that will hear the health care case is in some ways as extraordinary as the case itself.  For the first time since at least 1953, when Chief Justice Earl Warren joined the court, the justices are divided along not only ideological but also partisan lines: its five more conservative members were all appointed by Republican presidents and its four more liberal members by Democrats.  Add to that the conventional wisdom about which votes in the health care case are fixed in concrete: the four justices appointed by Democrats are thought certain to vote to uphold the law, and Justice Clarence Thomas, appointed by the elder George Bush, is believed to be a sure vote to strike it down.  The consensus among scholars and Supreme Court practitioners is that Chief Justice Roberts is unlikely to add the fifth vote to those of the four justices in the court’s liberal wing to uphold the law. But he is said to be quite likely to provide a sixth vote should one of the other more conservative justices decide to join the court’s four more liberal members.  Either way, then, the chief justice is likely to be in the majority. Indeed, in the last two terms Chief Justice Roberts has been in the majority at least 90 percent of the time, a distinction he shares with only Justice Anthony M. Kennedy, the court’s swing justice.  Should a closely divided court strike down the health care law, the decision will call to mind Bush v. Gore in 2000 and Citizens United v. Federal Election Commission in 2010. They were 5-to-4 rulings decided along ideological lines, but there were Republican appointees on both sides.  Chief Justice Roberts was not on the court when Bush v. Gore was decided (though he played a minor role in assisting George W. Bush’s legal team as a lawyer in private practice). Citizens United is another matter: it is easily the most divisive decision issued by the Roberts court and so one from which he may have drawn lessons.  “In all the years he has been on the court, there had been only one firestorm, and that was Citizens United,” Professor Friedman said. “And I don’t think he anticipated that reaction.”
Considered likely to join the Supreme Court majority either way the case is decided, Chief Justice John G. Roberts Jr. may never encounter a more important ruling.