History. 3 of 5. States filed first in 2018 and twice in 2019; groups filed first in 2019 and 2026.
Hunch.
The first-to-court market resolves on the filing dates in CourtListener and the filers' own releases: YES if states file before any campaign group, NO if a group files first. It is void if both file on the same day, if no one files by 30 November 2026, or if the rule has not appeared in the Federal Register by 9 October 2026.
We looked for cases where a new US government cancelled or weakened a binding rule made under a government of the other party, and opponents said in public, before the new rule came out, that they would go to court. We found five such cases, all since 2018. In every one, the first court challenge was filed by the day after the rule appeared in the Federal Register.