Presidents Harry S. Truman, Dwight D. Eisenhower, and Ronald W. Reagan embody a paradox. All three presidents made nuclear decisions ranging from hawkish and belligerent to dovish and restrained. How can such marked differences be explained? I argue that religious cultural heritage (RCH) can provide a parsimonious link which unifies the seemingly disparate nuclear choices of these presidents. I propose a theory to connect religious cultural heritage, decision-making frameworks, and nuclear choices. I apply this theory to Presidents Truman, Eisenhower, and Reagan at the individual level of analysis. Since these three presidents were immersed in a Christian cultural milieu, I move beyond the simplistic treatment of religion as a proxy for morality to explore both Christian thought on war and the philosophical ethics, philosophy of government, and philosophy of human nature which underlie Christian thought. Using secondary and primary sources including archival research, I analyze each president and his nuclear decisions. Each presidential chapter presents the RCH of each president, pieces together each worldview, establishes patterns of thought and patterns of action, and analyzes a number of salient nuclear decisions ranging from choices in the midst of crises to programs for nuclear sharing and cooperation. In the final chapter I discuss and integrate my findings through the lenses of history and policy science, present avenues for future work, and draw policy lessons which can be applied today. / text