My friend Laurence Tribe, the nation’s leading constitutional scholar who once had a student named John Roberts in his Harvard Law School class, had predicted the outcome.

In the face of the overwhelming consensus that the Supreme Court would strike down the individual mandate at the heart of health reform, Tribe has repeatedly said the issue was clear and the Court did not even need to reach the question of whether the mandate was a proper exercise of Congressional power over interstate commerce. Tribe said to me as late as yesterday that the Affordable Care Act offered people a choice: those who decided not to obtain health coverage have to pay a tax—which is plainly is a constitutional exercise of federal power.

The argument is both clear and compelling—and was the crux of the chief justice’s opinion. John Roberts may have forgotten the oath of office when he administered it to Barack Obama; he remembered his oath when he decided this case. Indeed maybe it is possible that Al Gore would have been president if Roberts had been chief justice in 2000. Yes, I know that he was part of the Bush legal team in Florida, but that is not the point. Given his politics, I am certain that Roberts would not have voted to pass health reform. But he did vote to uphold it; he did what a judge is supposed to do—follow the law, not his own politics.

The chief justice made the difference while Anthony Kennedy, who many had hoped might, instead joined the Three Horsemen of the Rightwing Apocalypse on the Court. One can disagree with many of Roberts’ choices—for example, his vote in Citizens United, which opened the floodgates for special interest money in campaigns. But he has now assured that the Roberts Court will be seen and remembered as more than an ideological rubber stamp.

The other lesson here? Don’t count Barack Obama out. He was supposedly doomed to fall to the inevitable Hillary Clinton just months before the Iowa caucuses. Health reform itself was doomed after the election of Scott Brown in Massachusetts—just months before Ted Kennedy’s dream of health care as a right and not a privilege was passed into law after a century of struggle.

And, according to the common wisdom, Obama re-election prospects are troubled. My response after today: just wait until November.

Barack Obama too was in Larry Tribe’s Constitutional Law Class at Harvard. And I guess that both he and John Roberts were paying attention.