Until now, the story of judicial review of the Affordable Care Act has been a simple one. Republican judges struck it down, Democratic judges upheld it.
Today, that streak has been broken in emphatic fashion, as the United States Court of Appeals for the 6th Circuit has voted 2-1 to uphold the law. And the critical vote was cast by George W. Bush-appointed Jeffrey Sutton (the other member of the majority was Carter appointee Boyce Martin, the dissenter was Reagan appointee James Graham, a judge on the Southern District of Ohio sitting by designation). You can read the opinions here.
There are a couple of reasons why Judge Sutton's vote is significant. There are judges appointed by liberals who are not all that liberal, and there are judges appointed by conservatives who are not all that conservative. Sutton, though, is the real deal. He's a rising star in conservative legal circles, a former Scalia clerk who has been praised even by ideological adversaries as a force to be reckoned with. He is a powerhouse, who has quite a bit of influence with the right. While I don't think it will have any effect on conservative's political demonization of the ACA, it might cause some movement amongst conservative legal elites.
The other thing worth noting is that this decision was made by the 6th Circuit. This is a court that has a reputation for being exceptionally bitterly divided. It is neither particularly left-wing or right-wing, but rather, it is divided straight down the middle, and the two camps are not friends with one another (a lot of this predates Judge Sutton's tenure on the court). There are a ton of cases that split the court, lots of exceptionally vitriolic dissents, even rumors of judges not speaking to one another based on years-long feuds. In other words, the 6th Circuit is not a place where liberals and conservatives typically band together to work on a common project: The Law. It is a place where liberals and conservatives are typically at one another's throats, looking to draw blood. That makes the bipartisan nature of today's decision all the more notable.