Doctor of Philosophy / Traditional military descriptions of conflict tend to focus on the movement of soldiers and armies across battlefields. When the airplane emerged, it forced military theorists to contend with a new, vertical, dimension of conflict. In America, the United States Air Force assumed an important role in this vertical dimension as the country's delivery mechanism for nuclear weapons. However, at the same time that politicians, academics, and military officials debated the offensive uses for aircraft a second debate occurred describing how best to use military means to defend the North American continent. Those who advocated for a defensive system to protect North American, including the President Eisenhower, strongly advocated for a continent-wide test of the new air defense system. That test was conducted once a year between 1960 and 1962 during which all civilian air travel across the U.S. and Canada was suspended. The tests were called the "Sky Shield" exercises. This research shows how a prevailing mood of fear and vulnerability gave air defense proponents the political capital to build a continental air defense network and test it during the Sky Shield exercises. Further, it describes the enduring legacy of this domestically-focused Cold War defense program. The research finds that America's approach to Cold War continental defense was strong when it was aligned with the White House's nuclear strategy, but when successive political leaders changed nuclear strategies that decision negatively influenced continental defense programs. This research is useful because it examines a relatively under-explored area of Cold War defense programs. Traditionally these studies focus on offensive capabilities far from American shores. This study instead examines homeland defense and how it changed during the Cold War as a function of changing nuclear programs and changing threats to the United States.

Doctor of Philosophy / Department of History / Mark P. Parillo / The Distant Early Warning (DEW) Line, a key program under President Dwight D. Eisenhower’s “New Look” policy, prepared the United States defense posture for “the long haul” in the Cold War. Eisenhower wanted to prevent the escalation of military costs while still providing an adequate defense. Eisenhower emphasized a retaliatory capability and improved continental defenses, the so-called “sword and shield,” which are key features of the New Look. The DEW Line would prove to be a vital component of both. Whereas the initial emphasis of the DEW Line was to warn against attack providing for both active and passive defense measures, soon there was a definite “counter-offensive” role for the DEW Line as well—the protection of the primary retaliatory capability of the United States: the Strategic Air Command (SAC). The place of the DEW Line in the history of the Cold War has been an under appreciated topic. With the exception of the scholarship from the 1950s and early 1960s, only recently have continental defense and particularly the DEW Line been removed from the shadows of other Cold War events, strategies, and military programs. This doctoral thesis is an account of the DEW Line’s conception, implementation, and position in Eisenhower’s New Look and deterrent strategy. The DEW Line proved to be a cardinal feature of Eisenhower’s New Look strategy: it strengthened overall U.S. defenses and defense posture as the one element of U.S. defense policy (“New Look”) that improved and connected both the active and passive measures of continental defense by providing early warning against manned bombers flying over the polar region; it bolstered the deterrent value of SAC; and it was instrumental in developing closer peacetime military cooperation between the United States and Canada. In fact, U.S.- Canadian diplomacy during the 1950s offers an important case study in “superpowermiddle power” interaction. However, despite the asymmetry in their relationship, U.S.- Canadian defense policies proved to be analogous. All of these objectives could not have been accomplished without the technological and logistical abilities necessary to construct successfully the DEW Line.