OPINION: Obamacare threatens to end John Roberts’s dream of a nonpartisan Supreme Court

The first time the Affordable Care Act came before the Supreme Court, its constitutional foundation under attack, John G. Roberts Jr. was its unlikely savior. In a spectacular display of spot-welding, the chief justice joined fellow conservatives on some points and brought liberals on board for others. Roberts was the only member of the court to endorse the entire jerry-rigged thing, and even he made sure to distance himself from the substance of the law. (“It is,” he wrote, “not our job to protect the people from the consequences of...