President Trump will soon turn his attention to another major campaign promise—rolling back the Obama climate agenda—and according to one quoted administration source his executive orders on that topic will “suck the air out of the room.” That’s good, but only if Team Trump finishes the job by casting into that vacuum the Paris climate accord.

That’s no longer a certainty, which ought to alarm anyone who voted for Mr. Trump in hopes of economic change. Candidate Trump correctly noted that the accord gave “foreign bureaucrats...