I don't think it is as fragmented as you explain it to be. There has been a broad agreement that the principles of the New Deal work; they have worked before and they would work now. However, there has been a deliberate effort by (a few) of the ultra-rich to subvert New Deal policies and this has been done through the creation and continued funding of institutions dedicated to what Krugman calls "movement conservatism". I would suggest 2 books: "Dark Money" and "Conscience of a Liberal" to get a better idea of the world that we operate in right now.