In Whitman v. American Trucking the court effectively ruled that administrative agencies can execute executive, legislative and judicial powers.
It is a win/win for pols and bureaucrats. The pols get to slough off the unpopular issues and look like heroes as they combat the evil bureaucrats, while the EPA can wage radical environmental jihad without worrying about those pesky voters.
I have never seen this dreadful truth expressed better than this. That is a concise explanation, beautifully stated, perfectly on target.