Fans of ObamaCare must be busting a gut three times over. The mandate that conservatives now hate was originally a conservative proposal. In upholding it, Chief Justice John Roberts followed President Obama's Rose Garden instructions to the letter: The Court must find an act constitutional if it happens to be the signature act of a president running for re-election.

Worse, in doing so, he may have read any constitutional limit on Congress out of the Constitution while pretending...