Americans are already deep in a culture war over morality-marijuana, abortion, same-sex marriage. We are already racially polarized over affirmative action and income inequality. And when we have ceased to be an English-speaking, Christian country and become instead an Asian-Hispanic-African-American-white nation, with large Jewish, Christian, Muslim, Hindu, Buddhist, agnostic and atheist minorities, and no defined borders, or common faith and culture, what holds us together?