Chua is no stranger to controversy, and her latest book is sure to provoke. She argues on the basis of psychological research that humans are hard-wired to prefer members of their own tribe and to regard outsiders with suspicion. Chua argues that American ignorance about the power of tribalism led U.S. officials to make costly errors in Vietnam, Iraq, and elsewhere. Her second point is more controversial: that the rise of identity politics is linked to a resurgent American tribalism that will ultimately divide Americans and undermine their common identity and the common good. Chua’s speculations about the future of U.S. politics are interesting, if unsettling; her portrayal of the consequences in foreign policy of ignorance about the power of group identity should be required reading for U.S. policymakers.