Second sentence of Kagan’s syllabus:
“ The States have devised mechanisms to ensure that the electors they appoint vote for the presidential candidate their citizens have preferred.”
The candidate the state’s citizens prefer! Not some other state’s citizens. Kagan did not have to phrase it that way. She could have just noted the supremacy of that state’s laws regardless.
The NPVC will be found unConstitutional.
These state compacts were approved by both houses of the legislature and signed by the governors. So you could posit that the State citizens approved/ preferred the the choice thru their elected representatives.
Maine and Nebraska allocate their electors by Congressional District.