I think once they are chosen, they become Constitutional officials no longer subject to state jurisdiction regarding their official duties, i.e., casting a vote for President & Vice President.
Just like Senators were free to vote how they wished despite being appointed by the states before they became popularly elected.
23 posted on 01/17/2020 1:51:38 PM PST by pierrem15
("Massacrez-les, car le seigneur connait les siens")