Todd Gaziano on Wednesday stepped into a meeting of free-market attorneys, think tankers and Republican congressional staff to unveil a big idea. By the time he stepped out, he had reset Washington’s regulatory battle lines.

These days Mr. Gaziano is a senior fellow in constitutional law at the Pacific Legal Foundation. But in 1996 he was counsel to then-Republican Rep. David McIntosh. He was intimately involved in drafting and passing a bill Mr. McIntosh sponsored: the Congressional Review Act. No one knows the law better....