The U.S. Supreme Court's decision in District of Columbia v. Heller constitutionalized the right of self-defense, and described self-defense as a natural, inherent right. Analysis of natural law in Heller shows why Justice Stevens' dissent is clearly incorrect, and illuminates a crucial weakness in Justice Breyer's dissent. The constitutional recognition of the natural law right of self-defense has important implications for American law, and for foreign and international law.