Few presidents understand the power of speech better than Barack Obama, and even fewer the power of denying it to others. That's the context for understanding the White House's unprecedented co-option of the Internal Revenue Service to implement a political campaign to shut up its critics and its opponents.

Perhaps the biggest fiction of this past year was that the IRS's targeting of conservative groups has been confronted, addressed and fixed. The opposite is true. The White House has used the scandal as an excuse to expand...