News accounts mention that California negotiated its standards in the form of an agreement with auto manufacturers. This was apparently a contract entered into lawfully as the waiver was in effect at the time.

Contracts have special status under the Constitution. Contracts between states and private entities cannot be abrogated by the Federal government (or any state government). The Supreme Court has upheld this several times.

Actually the status quo ante that was restored by yesterday's repeal dates from the GW Bush administration. And also the repealed rule was not all that different from the GW Bush standard.

I'm not sure why the Trump administration decided to have separate repeal and replace provisions, but it did.

You mischaracterize the 2015 rule, which largely codified existing practices that were put in place by the GW Bush administration.

Consequently, the federal jurisdiction outlined in the Obama rule was in some ways less far reaching than that during the Clinton administration. The Bush EPA had to scramble to implement a 2006 Supreme Court decision on Clean Water Act jurisdiction, and did it in a messy way. All the Obama EPA did was to implement the same standards in a less-messy way.

That story is describes the massive changes that the Trumps intend to make. The reporting compresses two things (1) repeal of 2015 reg and (2) new proposed rule not yet in effect.

Thought experiment: If yesterday's repeal resolves an egregious overreach, why the new rule?

That story is related, but is not about the rule that was repealed today. It is about a new rule that the Trumps say they will promulgate before the end of the year.

Recreational outrage from the right notwithstanding, the Obama rule was more of a technical fix--it did not substantively change the scope of jurisdiction that it inherited from the GW Bush administration.

The Obama rule in question did not actually make a substantive change to jurisdiction versus the previous administration--that's just spin from agribusiness.

Consequently, the repeal by itself does not change a whole lot.

However, it clears the way for a comprehensive new rule that actually is a huge departure from every previous administration (in the wrong direction). (It "clarifies" the Clean water act.)

They wouldn't do that if the "Obama overreach" narrative were true, because they just repealed that.

That's not accurate. The 2015 rule was just a technical fix. It did not change the definition of "waters of the U.S." significantly from the GW Bush administration.

If the Obama rule were the radical change that you cite, then repealing it would solve it and restore the status quo ante. But instead the Trump administration has prepared a new rule, still in draft, that would deregulate most of the wetlands in the U.S.

The repeal of the Obama-era rule does not actually change things much. It's the still-pending new rule that would deregulate most of the wetlands in the U.S.

Agribusiness has been somewhat successful in promoting the idea that the 2015 rule was some kind of "drastic overreach," and of course 3 minutes of Obama hate. But the Obama rule was actually just a big technical fix that just made the regulatory apparatus a bit more straightforward. It did not appreciably change the scope of regulation.

There is a new proposed rule pending from the Trumps that will make a radical change to scope, and in the wrong direction.