[Yo-Yo]

If the state decides to be part of that compact, it ties its electoral votes to the national popular vote. So it would force the electors to vote for the national vote winner.

If the SCOTUS rules that electors must vote for the winner of the popular vote OF THE ELECTOR'S STATE, then the electors would be legally bound to vote for the winner of their state regardless of any interstate compact.

[david1292]

That’s not what the case is about.

The states are arguing that the electors are bound to vote based on the state’s laws....whatever they may be. In other words, the electors have to vote how the state wants them to vote and not vote based on their own free will.

So the state could pass a law that says its electors are bound to the winner of the national vote. It would then be illegal for an elector to instead vote for the candidate that won their state.