illegal...unconstitutional as you point out so well......, won’t be effective anyway..
its all a publicity stunt trying to make HilLIARy look better on a post-mortem basis
Why is it illegal or unconstitutional?
It may be unconstitutional if they call it a compact.
But that is not necessary to accomplish their purpose.
The Legislatures of New York and California can appoint their Electors using whatever methods or procedures they choose. They can describe a mythical "national popular vote" in their legislation, and they can further define how it is to be ascertained.
Most importantly, though, they can bar any conservative or moderate candidates from their ballots. That is neither illegal nor unconstitutional, as long as we are talking only about ballots to designate Presidential electors.
Donald Trump received 7.2 million votes in NY and California. Delete those totals from a "national popular vote" and all states who have passed these laws will be casting their EVs for the Democrat.