[nradov]

The Western States Pact is in some sense a second parallel federal government.

https://www.gov.ca.gov/2020/04/27/colorado-nevada-join-calif...

Of course state governments have previously formed multilateral agreements on other topics such as water rights.

[ceejayoz]

It's been fascinating to watch several of these pop up, especially the big three (Western, Midwest, and Northeast).

https://twitter.com/johnrobb/status/1253455955666382848