This should be the first (of many) challenges Texas makes. The president doesn't have the authority to unilaterally enter America into treaties with other countries. That Obama called it an "accord" doesn't change the fact that this is a treaty. When Trump "withdrew" (we shouldn't use that word, it's linguistic warfare as we were never a part of this illegal treaty) he failed by not making it clear that we were never a party to this treaty as it was never ratified by congress.