Abstract: This paper explores U.S. government activities related to human experimentation after World War II. We emphasize how a proactive foreign policy, even in the pursuit of liberal ends, can undermine the rights and liberties of members the domestic populace. The typical primary justification for a strong military and proactive foreign policy is to protect the person and property of domestic people while reinforcing liberal values. But preparing for and engaging in war and foreign intervention, even if defensive in nature, often does the opposite in unseen and underappreciated ways. We discuss the implications of these tendencies and consider three responses offered by liberals—liberal empire, interstate federalism, and citizen-based defense.