With a special prosecutor, the probe would immediately move to the shadows, and the Administration and the IRS would use it as an excuse to limit its cooperation with Congress. Special prosecutors aren’t famous for their speed, and a decision on indictments would extend well past the 2014 election. If there were no indictments, whatever the prosecutor has discovered would stay secret. And even if specific criminal charges were filed, the facts of an indictment couldn’t stray far from the four corners of the violated statute.

Beyond proving his specific case in court, a special prosecutor will not be as concerned with the larger public policy consequences and political accountability. That accounting should include how this started, what IRS officials thought they were doing, how far the knowledge and genesis went up the chain of government command, or what pressure was brought to bear on those supposed “rogues” in Cincinnati. …

Calling for a special prosecutor is a form of cheap political grace that gets a quick headline at the cost of less political accountability. Congress can do the investigating first, and if it discovers criminal behavior it can make that known and refer the cases and evidence to Mr. Holder, who will then be accountable if he refuses to act.