Chief Justice John Roberts last week did something that, in polarized Washington, may turn out to be more important than saving Obamacare.

He showed that compromise can be consistent with principle. More than that: He showed that compromise, for someone who respects and knows how to use the democratic process, can be the best way to advance principle.

It would have been unhealthy for the country if five Republican-appointed justices had nullified the Democratic-approved health care law. Honoring what he called "a general reticence to invalidate the acts of the Nation's elected leaders," Roberts led the court away from that fate.