Because the laws are about particular things in the real world that have nothing to do with the legal system. They are frequently about scientific matters, for example. What constitutes a threat to public health? What constitutes pollution of a waterway?
When Congress authorizes an agency to maintain, say, clean drinking water, it entrusts scientific experts to determine, based on the most up-to-date evidence, what constitutes a pollutant that is harmful to human health. We do not need Congress to pass a new law every time we get new scientific evidence that a particular chemical (say, PFAS), is harmful.
The laws have nothing to do with the legal system? That's a new one.
Thats all people here want. Whatever power it is that you think that agencies should have, try to pass a law to do that first.
SCOTUS just decided that despite the madnates existing, being funded, and being regularly renewed, that's not good enough.
But they haven't defined how specific the mandate and laws must be. They can just, you know, keep shifting the goal posts until they get the desired result.
Then make a law saying that yes this is ok and good enough.
Problem solved.
The statutes regulating agencies are generally broad signposts, giving the agency a mission statement and a direction but leaving it a large latitude to implement it and decide on the details. That latitude has a legal implication since the agency is generally responsible for setting and enforcing standards.
The Chevron Deference is the legal doctrine that since congress delegated its power to the agency as matter and implementation experts, the agency's policy decisions should be deferred to so long as:
- it's legally ambiguous aka congress has not answered the precise issue themselves
- it is a permissible construction of the statute
The entire point of the chevron statute is that it's not up to the judicial branch to set government policy, and if a problem is a legal void then they have no authority, and unless and until congress makes a specific decision the agency does.