Vol. 120 No. 7 Part I argues that the right to medical self-defense is supported by the long-recognized right to lethal self-defense: the right to protect your life against attack even if it means killing the attacker. The lethal self-defense right has constitutional foundations in substantive due process, in state constitutional rights to defend life and to bear arms, and perhaps in the Second Amendment. But even setting aside those constitutional roots, the right has long been recognized by statute and common law. Even if the Supreme Court stops recognizing unenumerated constitutional rights, legislatures should presumptively protect people’s medical self-defense rights just as they protect people’s lethal self-defense rights. While a legislature need not fund people’s self-defense, it generally ought not substantially burden people’s right to defend themselves.