Repubs complain all of the time because they are in a coalition with groups they don’t like, but need to win elections – and when they lose they blame the other wing of the party. It’s usually the “fiscal” v.s. the “social” cons that duke it out.

There already are plenty of other parties – the Libertarians, Greens and Constitution come to mind – but Repubs won’t join them because they know they can’t win elections that way.