Thanks Jane. The way I see it is as follows:
(1) Article III gives the Supreme Court jurisdiction over the case.
(2) The fact that the voting in other states can result in Texas being sent off to war gives Texas standing, at least for the national office elections in other states.
The jurisdictional problem isn’t the “between two or more states” part, but the “controversies” part, a component of which is standing. While the Supreme Court has original, as opposed to appellate, jurisdiction over controversies between states, there has to be a “controversy” in order for there to be any jurisdiction at all, which means the state filing the lawsuit has to have standing.
I think the idea that Texas has standing because its citizens could, hypothetically, be sent off to war in the future by a President who was elected by electors who were improperly appointed by another state would stretch the concept of standing to the point that it becomes meaningless as a limitation on judicial power.
Depending on the specific complaint, there are scenarios where the campaign, the elector candidates from that state, the state legislature (or individual legislators), or even individual voters from that state may have standing to sue over various issues regarding the appointment of a state’s Presidential electors. But I don’t see any scenario where another state would have standing.