There’s a debate about whether Congress can delegate authority to a bureaucracy, as it has done here. Congress has the right to yank that authority away or banish the bureaucracy.
Not much of a debate. We have three distinct branches of government so as to limit the power of any one branch. Our Constitution is explicit:
Executive - executes laws
Legislative - makes laws (they were also intended to be the most powerful branch yet slow and lumbering so as to protect liberty)
Judical - decides if laws are Constitutional or not
The executive has no authority to make laws.
The legislative cannot delegate its authority to the Executive.