It works both ways. In 2004, Bush would have received all of CA's electoral votes because he had won the popular vote, presuming CA signed on to this compact. In 2000, Gore would have received FL's electoral votes.
You can bet your last dime that when this stupid idea goes against the left, they'll sue and try to get it not to count "this time".
Agreed. But still, in a system driven by the popular vote, the preponderance of the electoral power will reside in the blue bits.
Red regions will at best have a marginal influence on the outcome ... they have to provide "just enough" blue votes for the Democrats, and no more.
The left's reasoning -- probably sound -- is that they can reliably carry majorities in the large population centers, without too much effort. Then they could carefully choose where in the red states to get the marginal percentages needed to create a national majority.
In contrast, Republicans would have to pour in a lot of effort and money to gain a majority in the high-population areas, with little hope of success -- and the red states as a whole don't have large enough red majorities to overcome the difference.
The net result is that the blue areas will control presidential politics, and obviously that favors the Democrats.
So we'll end up with regional strife -- the dense "enfranchised" ruling over the scattered disenfranchised. There's a lot of ugly world history that has flowed from such dynamics.