The Republican Party as it was known before 2015 is, yes. Come 2019, there will still be an obvious split - those who identify with the alt-right vs those who are "classic" republicans. This will likely split the decision again between a candidate like Trump (if not him

vs. someone like Rubio, with a more progressive viewpoint). Same goes for the democratic party, too, i.e. someone like Bernie vs. a "classic" democrat.