The controversy over birthright citizenship has generally been framed as a dispute over the meaning of a single sentence in the Fourteenth Amendment. Does the Citizenship Clause constitutionalize the English common-law rule that virtually every person born within the sovereign's dominions is a citizen? Or does it merely codify the narrower understanding reflected in the Civil Rights Act of 1866, under which citizenship required not only birth within the United States but complete political jurisdiction—that is, allegiance to the United States rather than to another sovereign? In this Provocation, John Eastman traces how one people, dissolving their political bonds, transformed the very nature of political membership and how that understanding has been fundamentally undermined over the last century.