The Republicans work lock-step and are devastatingly good at politics. Because 100% of their resources are dedicated to winning elections. They appeal to people base emotions, not their intelligence. However, Republicans are terrible at governance.
Democrats are disunited and individualistic. They appeal to people's intelligence, not their emotions. They stink at politics and at winning elections. However, Democrats are (in general) good at governing.
Logically, if people voted based on intelligence, the GOP wouldn't win any elections, and the Dems would sweep all.