This is an alternate history where both Texas and Deseret are admitted in their full statehood glory. The rules are simple you can't give deseret or Texas any more land but you can't take away any land from them either. Any territories that weren't states before the treaty of Guadalupe Hidalgo are fair game.
Here is a map for reference
(Ignore the part of Deseret that's past Texas)
https://twitter.com/6c2b646f30d540d/status/1161830821151596545?s=09
Here is a map for reference
(Ignore the part of Deseret that's past Texas)
https://twitter.com/6c2b646f30d540d/status/1161830821151596545?s=09