Yes, it's about attacking the means by which we collectively hold bad actors in check. Also other countries absolutely do delegate regulatory minutae to experts. If we can delegate law making to elected representatives, we can do the same for regulations to ensure they do what is intended.

No, it is about decent lawmaking. Nothing stops Congress from delegating regulation-making powers to agencies. Chevron isn't about that. Chevron didn't involve any delegation of anything.

Chevron is about the statute saying something vague like "a term in a consumer credit contract is void if it is oppressive" and then the effective definition of the word "oppressive" being able to be "interpreted" by executive agencies at their whim with the courts being powerless to intervene. That is contrary to the rule of law. If there is a vagueness, that should be filled by a court supplying an interpretation and that precedent is then established. Law should be stable and predictable.

Remember the original Chevron case was based on the EPA changing its interpretation of "source" of air pollution under the Clean Air Act 1963 to make it much narrower. There was no statutory power for it to do so. Nothing in the Act authorised it. It unilaterally changed its interpretation of the law, and the Court said "that is fine, it is ambiguous, you decide what the law is and as long as it is a reasonable interpretation that is fine". Nothing to stop them turning around the next day and changing their interpretation again.

> being able to be "interpreted" by executive agencies at their whim with the courts being powerless to intervene.

This isn't accurate though. You're arguing these things could literally change day to day, but there were established procedures for rule changes. Those procedures required posting reasons for the change, a notice published in the register, the chance for people to comment on the change, etc. When regulations changed without notice and without any reason given they got blocked from making the change.

See the debates around net neutrality and FCC decisions. Took a lot of notices, a lot of back and forth, etc. They couldn't just arbitrarily change the rules from one day to the next.

> Nothing to stop them turning around the next day and changing their interpretation again.

Why describes mostly every law enacted by a parliament? They clearly have that power to change the laws they enacted at any time.

So where is the problem if parliament delegates this power to some executive entity?

Now, if delegation is not clearly defined, this is another issue I can understand. And I am not interested enough in the minutia of US legislation to have an opinion on that.

> Why describes mostly every law enacted by a parliament? They clearly have that power to change the laws they enacted at any time.

They don't have the power to reinterpret their laws. They can repeal laws and pass new laws, but interpretation is up to the courts, if they don't like the interpretation the court gives to a law then their recourse is to pass a new law.

> So where is the problem if parliament delegates this power to some executive entity?

The problem is firstly that the executive isn't supposed to have the power to make or repeal laws, "delegating" it to them breaks the separation of powers, and secondly allowing a law to be "reinterpreted" rather than rewritten breaks the whole system of precedence that the rule of law depends on.

> then the effective definition of the word "oppressive" being able to be "interpreted" by executive agencies

I don't get how this could ever be resolved though. You can complain about how "oppressive" is "interpreted" so they can add more words, they can say "people are harmed" and then it's up to interpretation about who is "people" and what is "harm" so then you add more words to define "people" as living homo-sapiens and then it's up to interpretation about what is "living" and on and on.

> If there is a vagueness

There is literally always vagueness. "I never said she took his money" can have 7 different interpretations just based on which word is emphasized.

It's a meaningless tautology that any English sentence has some amount of vagueness and that people will be interpreting its meaning.

Which is exactly why it's important to have a separation of powers where the legislature writes the laws and the courts interpret them. When the same entity is both writing the rules and interpreting the ambiguity in them, that's ripe for abuse.

Chevron was not about deciding regulation details.

It was about who interprets what a law an agency administers means.

Before Chevron, an agency could say "we interpret this law to mean we can do X", and then no one could stop it from doing X. That's a huge amount of unchecked power!

Now an impartial court get to interpret what laws mean. Seems like the obviously right thing to me.

Here are two examples.

First, a made up but illustrative one. The statute says something vague like "a term in a standard form consumer contract that is oppressive or unconscionable is void." In a common law system (anything derived from English law, including US, Australia, etc) the meaning of these terms, if they aren't defined elsewhere in the statute, is figured out based on decided cases. Someone will argue that it covers a particular clause, and the judge will decide if it does. The judge might give a detailed test for what constitutes "oppressive" or might reuse an existing one from a different context or whatever. The decision might be appealed and a panel of judges decide the meaning. But over time, and as cases are decided, the meaning becomes clear. You can point to half a dozen examples of clearly oppressive clauses and a dozen that clearly aren't, there is a legal test for what counts, etc. The law develops towards certainty and the doctrine of precedent also means it stabilises: it isn't going to change its meaning just because new judges are appointed, because they generally follow precedent pretty closely.

Under the Chevron doctrine, there is an extra step. If a government agency says that its interpretation is that "oppressive" means X, then if that interpretation is reasonable, if it is open on the wording of the statute, then the inquiry stops there. The court defers to the government agency. This has the benefit, admittedly, that the definition can change over time according to changing conditions. But it has downsides. It is giving the job of deciding what laws mean to the government, rather than the judiciary. The government is meant to act according to law, not to interpret it. That isn't the executive's proper function. But quite apart from the philosophical objections, it is no good for stability. A new government is elected and the official interpretation changes. This happens a lot. A new government is elected and it is decided that now "restraint of trade" clauses in employment contracts are legal. Four years later they're unenforceable. Four years layer they're enforceable again. No laws changed, no regulations are passed, a government agency just releases a new statement of its official interpretation of the law.

That is quite different to, e.g., there being a statute saying "terms in consumer contracts must accord with the regulations promulgated by the department of consumer protection as in force at the date of execution of the contract" because:

1. It is clear what is delegated to the executive and what is not.

2. It is clear that the definition applied is the definition at the time the contract was signed, and the "interpretation" is not retrospective.

3. It is still up to the court to give a clear, consistent, precedential ruling as to the meaning of the regulations themselves.

This example is real: Chevron itself. There, the EPA changed the definition of "source" of air pollution, without Congressional approval, so that "source" was much narrower (making pollution harder to regulate).