[CORed]

The Constitution in fact leaves the means of choosing electors to the states. There is no requirement in the constitution that the electors vote for the winner of the popular vote in that state or that there even be a popular vote. Electors could be chosen by the legislator, appointed by the governor, or selected by a lotter from all the citezens of that state, without violating the Constitution.

So the movement to have states assign their electors to the winner of the national popular vote, regardless of whether you think it's a good idea or not, is perfectly contitutional.