Republicans stand for strong tribalism - doing only what the tribe approves and not applying any actual rationality to it. Insanely pro-team people are regularly kicked out of this party for mild disagreement with a small subset of this weeks ideals.
Democrats stand for weak triablism - they are sort of in the same camp on some stuff, but generally are allowed to disagree with the cult on things too. No one is kicked out, but bickering gets in the way of standing up to a strong voting block of the super-tribalist republicans.