From my link: Some supporters and opponents of the NPVIC believe it gives one party an advantage relative to the current Electoral College system. Former Delaw

From my link: Some supporters and opponents of the NPVIC believe it gives one party an advantage relative to the current Electoral College system. Former Delaware Governor Pete du Pont, a Republican, has argued that the compact would be an "urban power grab" and benefit Democrats.[19] However, Saul Anuzis, former chairman of the Michigan Republican Party, wrote that Republicans "need" the compact, citing what he believes to be the center-right nature of the American electorate.[33] A statistical analysis by FiveThirtyEight's Nate Silver of all presidential elections from 1864 to 2016 (see adjacent chart) found that the Electoral College has not consistently favored one major party or the other, and that any advantage in the Electoral College does not tend to last long, noting that "there's almost no correlation between which party has the Electoral College advantage in one election and which has it four years later."[32]