Yes, states’ powers to choose electors by popular vote, if their legislatures decide to choose electors that way, are constrained by their peoples’ rights under the 14th, 15th, 19th, 24th, and 26th Amendments. Those amendments confer rights on individuals, not on other states. Texas has no standing to sue over the violation of another states’ citizens’ right to vote.
I don’t agree. The Civil rights acts of the 1960’s mentioned that people have a right to vote without impediment. Impeding voting, at the time by literacy or violence, is what was intended. However, if you allow election fraud, your impeding voting because it doesn’t matter. The outcome of preventing someone from voting with laws, or allowing someone to break the law, to prevent someone’s 14th Amendment right, is the same.
Every State has a dog in that hunt. So, Texas has a claim.