With the presidential battle begun, the Obama campaign has revived the Cold War nuclear strategy of launch on warning. At any suggestion that a conservative idea might be threatening its ideological fortress, the American left now launches ICBMs of rhetorical destruction.

So it was after the Supreme Court's hearings on the Obama Affordable Care Act, which put in jeopardy the federal command to buy health insurance. After the president green-flagged the assault, the Supreme Court's "legitimacy" was in play. The Roberts Court,...