I am not sure what is your point; but I think you are saying, given that the SCOTUS has confirmed states have comprehensive rights to appoint Electors, the proposed NPVI is lawful. I disagree; and so does Professor Lowenstein, UCLA (LAW). See, regardless of whether a state’s Appointment of its own Electors can be said to be consistent with the Constitution; the Constitution definitely does not say, one state can ‘pick’ the Electors of another. And by compelling Electors to cast their votes in accordance with the votes in other states, the NPV law essentially converts one state’s Electors into Electors acting as if they were Appointed by another. The state has no legal right under its plenary authority, to give away its Electors.
The Founding Fathers only said in the U.S. Constitution about presidential elections (only after debating among 60 ballots for choosing a method): “Each State shall appoint, in such Manner as the Legislature thereof may direct, a Number of Electors . . .” The U.S. Supreme Court has repeatedly characterized the authority of the state legislatures over the manner of awarding their electoral votes as “plenary” and “exclusive.”