The U.S. Supreme Court recently heard arguments on Relentless v. Department of Commerce. At issue is whether the Department of Commerce under its mandate to prevent overfishing has the authority to mandate that fishing boats must be required to pay the salary of a government game wardens riding along on their fishing expeditions to police whether any overfishing is occurring.. The fishermen think that policy is not only a bad one but unconstitutional and potentially financially ruinous. The government cites Chevron deference in saying that the courts should defer to the best judgement of regulatory agencies.
The problem is that this policy makes the following scenario probable. First, Congress votes to do what they think is a very good thing. In this case prevent overfishing. But rather than get involved in the messy details of how to actually do that, they simply create an agency to achieve the end they are looking for in whatever way the agency wants Then the President appoints the agency personnel. Depending on the political leanings of the President, it's quite possible that the agency gets staffed with zealous political idealogues. Those partisans then get the privilege of effectively writing law by drafting the enforcement rules and regulations. If the regulated industries don't like the new regulations they have to appeal to an administrative law judge of the agency that drafted the regulations, not an independent court. Then when the agency, predictably, says their regulations are just fine, outside courts refuse to hear an appeal because of Chevron "deference".
In Relentless, the Supreme Court is considering whether to modify or overturn this Catch 22 in the legal system. In oral arguments, the three liberal justices are, predictably, arguing to retain Chevron deference. The three conservative Justices are making noises about overturning Chevron. And the three moderate Justices are trying to cobble together some middle ground. The danger is that we'll end up with a mess like the Roberts decision on ObamaCare or the Kennedy opinion on what constitutes wetlands.
Still, any decision that lessens the current system where regulatory agencies are effectively the writers of laws, the enforcers of the laws they write and the judge on whether their laws are constitutional, will be a long sought step forward.