Command and control systems of new nuclear states are likelv to fail when placed under stress. This thesis will demonstrate that such failures can dramatically affect regional or international stability. Describing the current argument over the consequences of nuclear prolifera -n between proliferation pessimists and deterrence optimists, ti. Dn-.., shows how C2 is in fact the crux of the debate. This thesis develops an analytical tool that may be applied to new nuclear states in order to classify their C2 systems and to predict when and how these evolving systems might fail. To show the tool's usefulness, it is applied to Ukraine, an important new nuclear state. This thesis also suggests several implications for U.S. foreign policy.