With all due respect to the author, this is not correct. First of all, the Constitution only sets forth the amount of Electors per state and says the method for which they are allocated is up to the state legislatures. Second, this is practice that has been in place since very first election by some states and changed over time. Many states for many presidential elections had all Electors appointed by the state legislature and there was no popular vote.
Now, that doesn't mean this is a good idea, and it's fine for him to have an opinion that it is not, but there is nothing unconstitutional or unprecendented about it - in fact this has been done since the first election. Personally have an issue with it as it would make Electoral votes also subject to gerrymandering.
George Will is due no respect. He's the token conservative for the inside the beltway crowd. He writes better about baseball than politics.
His constitutional ignorance is very much on display here. That's exactly why he is the token conservative for the inside the beltway crowd.