[twoodfin]

You are, I believe, correct.

States can pick any means of selecting their electors that doesn’t conflict with other provisions of the Constitution. Obviously, a state imposing a requirement that electors be white or male would not fly.

OK, so they choose to have a state election. It must be a fair election, affording due process to all the voters as that is Constitutionally understood (one person, one vote, for example).

“We’ll have an election, but if national results go a different way, we’ll throw out the votes of the ‘wrong’ voters,” is … not that.

An analogy: Could the southern states agree to a compact to elect their governors by party slate? I doubt that would pass muster, and neither would the popular vote compact.