Since its creation, the public and policymakers have shared two common perceptions regarding the cyber domain: fear and optimism. Polling reveals that the public fears cyber attacks more than any other form of conflict or crime. Similarly, elites often equate the potential consequences from cyber attacks with established weapons of mass destruction, while also expressing optimism that cyber weapons will shorten wars and spare lives. Increasingly, this combination of fear and optimism is reshaping foreign policy, military strategy, and public morale. The US government’s cyber operations budget is now comparable to the US nuclear triad budget. Nuclear budgets grew in response to the overwhelming power the weapons demonstrated in WW2; this type of demonstration event has not occurred in the cyber domain. While cyber threats are increasing, the actual damage they have caused to date is negligible compared to established domains of military conflict. Moreover, cyber attacks have shown little ability to alter the political calculus of a state, meaning optimism about the capacity of cyber to reduce the length of conflicts is unsupported. In this proposal, I offer a framework to explain why the perception of cyber conflict appears disconnected from the historical record and show how this combination of fear and optimism shapes US policy in the domain. My argument relies upon established concepts in the international relations literature concerning how decision-makers process national security threats. Cyber optimism is rooted in a pervasive belief that cyber offense trumps cyber defense, while cyber fear stems from the inherent difficulty in distinguishing between offensive and defensive cyber operations. In this dissertation, I examine three dimensions of the relationship. First, I evaluate the generalizability of my argument through a comparative analysis of the air domain in the early 20th century and the modern cyber domain. Second, I conduct a survey experiment of 1,000 US residents and a second experiment on 64 cyber experts to test the validity of my theory. Third, I utilize process-tracing to analyze the development of US cyber policy from 1986 to 2014 to show how these causal mechanisms functioned during policy debates.