When Justice John Paul Stephens issued his 1984 opinion in Chevron U.S.A. v. National Resources Defense Council, he started what legal scholar Gary Lawson later called “nothing less than a bloodless constitutional revolution.” At long last, on Wednesday, the Supreme Court will hear two cases that may signal the beginning of the end to that revolution. Article I of the Constitution explicitly directs that “All legislative Power herein granted shall be vested in a Congress of the United States,” not regulatory agencies. Yet Justice Stephens’ opinion found that “agenc[ies] may . . . properly rely upon the incumbent administration’s views...