In his 1933 inaugural address, Franklin D. Roosevelt declared that "the only thing we have to fear is fear itself." Yet even before Pearl Harbor, Americans feared foreign invasions, air attacks, biological weapons, and, conversely, the prospect of a dictatorship being established in the United States. To protect Americans from foreign and domestic threats, Roosevelt warned Americans that "the world has grown so small" and eventually established the precursor to the Department of Homeland Security - an Office of Civilian Defense. At its head, Roosevelt appointed New York Mayor Fiorello La Guardia; First Lady Eleanor Roosevelt became assistant director. Yet within a year, amid competing visions and clashing ideologies of wartime liberalism, a frustrated FDR pressured both to resign. In Defenseless Under the Night, Matthew Dallek reveals the dramatic history behind America's first federal office of homeland security, tracing the debate about the origins of national vulnerability to the rise of fascist threats during the Roosevelt years. While La Guardia focused on preparing the country against foreign attack and militarizing the civilian population, Eleanor Roosevelt insisted that the OCD should primarily focus on establishing a wartime New Deal, what she and her allies called "social defense." Unable to reconcile their visions, both were forced to leave the OCD in 1942. Their replacement, James Landis, would go on to recruit over ten million volunteers to participate in civilian defense, ultimately creating the largest volunteer program in World War II America. Through the history of the OCD, Dallek examines constitutional questions about civil liberties, the role and power of government propaganda, the depth of militarization of civilian life, the quest for a wartime New Deal, and competing liberal visions for American national defense - questions that are still relevant today. The result is a gripping account of the origins of national security, which will interest anyone with a passion for modern American political history and the history of homeland defense.