Read the Constitution, plus the 12th Amendment.
The States are free to choose their electors how they like. They are not constrained to allocating all of their electors based on whoever gets the majority of the state’s vote in the presidential election election in November. Changing the method that a state selects electors does not change the “electoral college”. (For what it’s worth: my view is that the most critical aspects of “electoral college” is that states get electors total to their number of Representatives+Senators and that it is those electors’ vote, not popular vote, which determines who becomes president.)
Maine and Nebraska are well within the constraints of The Constitution in the way they choose electors.
Any State could conceivably appoint the richest person in the state, or the governor, or the school board presidents, or their Nobel Prize winners, to choose their electors.
PS: The Constitution does not contain the phrase “Electoral College”
Awarding electors by congressional district is the way that is most representative of the people in my opinion. It also negates the effect of fraud in places like Detroit where 2 electoral votes would be given whether they get 10 votes or 10 billion.
While most people don’t like the idea of allowing state legislatures to choose senators, it was the more representative means before the 17th amendment. Now urban centers choose senators by popular vote. Its why a conservative majority state like Michigan gets Levin and Stabenow again and again.
I am fully aware of the constitutional provisions for electing a president. If you had read my all of my posts, you would have read my reference to what some states were proposing to make the overall popular vote their guidance as to how to allocate their electors. BTW Hillary Clinton was pushing diminish the role of the electoral college(excuse for using language which most people will comprehend. I happen to believe the electoral college as presently constituted is an effective way of minimizing a tyranny of the majority.