No State shall, without the Consent of Congress, lay any duty of Tonnage, keep Troops, or Ships of War in time of Peace, enter into any Agreement or Compact with another State, or with a foreign Power, or engage in War, unless actually invaded, or in such imminent Danger as will not admit of delay.
So it ain't gonna happen!
That is correct.For the California plan to be legal,the Constitution would need an amendment allowing it to do so.Otherwise, whoever won the state gets its electoral votes(now the electors are not bound to vote for who they are pledged to vote for,but that’s another story....)