You can tell the regulation beat has reached critical political mass when even the folks at Politico are pushing it on the home page. “Obama’s agencies push flurry of ‘midnight’ actions,” the political website reported recently, adding that Republicans are preparing to block or repeal as many as of these and previous rules as possible.

This effort is going to be a political brawl—not least due to resistance from the bureaucracies in the executive branch and perhaps even some political appointees who go native quickly. If Donald...