Washington CNN  — 

He did it again.

Chief Justice John Roberts stepped in once more to vote in favor of the Obama administration’s signature legislative achievement: health care. In a 6-3 decision, he sided with the President, just like he did in 2012, the first time the justices reviewed the controversial law.

And this time, he peeled off the vote of Justice Anthony Kennedy, the Court’s perennial swing vote who opposed the administration in the last Obamacare decision.

Roberts has long been aware that if the Court voted against the government, it would severely – if not critically – destabilize the law. But before Thursday, even those who are deeply familiar with the chief justice’s jurisprudence had no idea how he was going to view the case. Indeed, at oral argument, he kept his cards unusually close to the vest asking hardly any questions. Perhaps he knew back then that it was likely he would write the crucial decision.

Here are four things we learned Thursday about Roberts and his stewardship of the nation’s highest court.

He wants to keep the Court out of Washington’s partisan gridlock

Perhaps more than any other justice now on the bench Roberts cares about the Court as an institution. After all, even though he only has one vote, the Court bears his name.

The growing public perception that the Court is politicized is clearly a concern for him. In a speech in Nebraska last year, Roberts talked broadly about the state of affairs in Washington – particularly the dysfunctional Congress.

He said that the “partisan rancor” of Congress “impedes their ability to carry out their functions” and stressed “I don’t want this to spill over and affect us.”

“That’s not the way we do business,” he said.

Roberts argued the Court was not composed of “Democrats and Republicans” in the way it goes about doing its job.

In 2012, some believe he took the Court’s reputation into account as he considered the previous health care case. That challenge—NFIB v. Sebelius—was argued in the shadow of the election and the stakes were higher. The Court was considering whether the law violated the Constitution.

Supporters of the law praised the decision back then, saying that although the Chief made clear he was no fan of the Affordable Care Act, he had based his vote on legal reasoning, not politics.

Perhaps that calculation came into play again. Roberts didn’t want the Court to look political, even though he concluded the act does not “reflect the type of care and deliberation, that one might expect of such significant legislation.”

But maybe he didn’t see this case the same way as the 2012 challenge. While the last time around, the Court considered the constitutional implications, King v. Burwell was a different kind of case. The Court was charged with interpreting the language of the law, something it does all the time.

In statutory cases, the Court looks at the contested language to see if it is clear one way or the other. Roberts said that although the language at issue was ambiguous, the statute’s purpose was clear.

“This case has always been a fairly straightforward dispute over statutory text wrapped in highly fraught political baggage,” said Stephen I. Vladeck, of the American University Washington College of Law who is also a CNN contributor. “And what’s especially revealing about the Chief Justice’s opinion today is that he focused entirely on the straightforward legal dispute, and left the baggage at the proverbial curb.”

He’s not scared of conservative criticism

Roberts stunned and angered conservatives when he cast the deciding vote to uphold the law under Congress’ taxing authority.

Roberts also showed with his vote Thursday that he is not overly concerned with conservative backlash. In 2012, commentator Glenn Beck went as far as producing t-shirts depicting Roberts and the word “coward.”

The vote bolsters the notion that Roberts wasn’t moved by such criticism.

Critics will say his move was baldly political and that once again he moved to save a bad law. Here’s what Justice Antonin Scalia said in dissent: “Normal rules of interpretation seem always to yield to the overriding principle of the present Court: The Affordable Care Act must be saved.”

During his Senate nomination hearing in 2005, he famously described the role of judges as similar to umpires who simply calls “balls and strikes” and stay away from the glare of the game.

Some see his vote on Thursday as further evidence that Roberts is living up to that pledge.

He thought through the real-world implications of the ruling

Unlike the 2012 challenge, when the law was brand new and hardly in effect, this time around millions of people were utilizing subsidies they thought the law authorized.

Did the consequences give him pause?

At oral arguments, Scalia pushed back at the government’s argument that a ruling against the government would have catastrophic effects. Scalia suggested the issue could be handled effectively by Congress.

But Roberts chose not to send the law back to Congress for a fix.

As the most senior justice, Roberts could have buried his vote by assigning the opinion to someone else to write. But clearly, he thought the case was important enough and garnered a 6-3 consensus, that it should be written by the Chief.

He looked beyond four key words

Despite his strongly conservative record on the Court, Roberts was not swayed by Justice Scalia and Thomas’ method of not looking beyond the four words, “established by the state.”

Instead, he looked at the law as a whole and the intent of Congress.

“While the meaning of the phrase ‘an Exchange established by the State’ may seem plain when viewed in isolation, such a reading turns out to be untenable in light of the statute as a whole.”

He also said: “Congress passed the Affordable Care Act to improve health insurance markets, not to destroy them. If at all possible, we must interpret the Act in a way that is consistent with the former, and avoids the latter,” he said.

His critics will say that the Obama administration re-wrote the statue, and it’s not the Court’s job to do an editing job for Congress.