This is clearly a risk-management issue.
California, Oregon and Minnesota sued President Donald Trump and several top cabinet officials over the administration’s requirement that federal agencies delete two regulations for every one they add.
Lodged by three Democratic state attorneys general, the lawsuit asserts that Trump’s January 2017 executive order and accompanying Office of Management and Budget guidance violate the U.S. Constitution’s separation-of-powers principle.
U.S. District Judge Randolph Moss ruled in February 2018 that a lawsuit led by Public Citizen to invalidate the rule failed to show the legal harm needed to pursue the case. [Source]
The judge was wrong. Regulations stem from statutes. Statues are legislation passed by Congress and signed into law by the President or vetoed and then overridden by the Congress. In no case does the President have the authority to simply refuse to regulate statutory law. The first function of the office of President is to execute statutory law so long as that law is constitutional. Trump has made no such constitutional distinction. No "harm" is required to rule as such as a federal judge.