Humanity possesses a variation in morality or worldview, created by evolution to allow man to adapt to different ecosystems. In the primitive world, finding consensus between those views was the method of resolving disputes. Once cities emerged, local and central governments assumed power over moral decision-making and made rules for an entire society. Later, the Enlightenment reopened individual morality as expressed by political parties, but today, those political parties represent tribes with radically different ideologies. Tribalism threatens to destroy the American political system because there is no consensus regarding the political morality of the United States. Tribalism impedes the federal government's operation because the political parties fight rather than negotiate. Ultimately, the American political system will fall if its people cannot overcome their tribal obsession.