The Soviet Union, in its drive to mobilize its every resource to turn back the German invaders, used a unique institution: the Gulag, a forced-labor, detention, and exile system isolating millions of citizens from the body politic.While the term “Gulag,” an acronym of “Glavnoe Upravlenie Lagerei” (Main Administration of Camps), properly notes a specific, time-limited administrative institution tasked with oversight of the Soviet detention system, I use the term here and throughout in its more common usage since the publication of Solzhenitsyn's works to refer to the entire Soviet penal system. This essay seeks to understand the wartime Gulag both as a microcosm of the Soviet home front and as an integral participant in the campaigns to mobilize Soviet labor power in support of the war effort and to cleanse that very labor force of real and potential enemies of the Soviet state. Focusing on the institutions and population, economic production, political education, and the rigidification of detention of those defined as “especially dangerous,” the essay explores the relationship between the Gulag and the larger Soviet polity. Although in economic and administrative terms the Gulag emerged as a burden to the Soviet state during the war, the Soviet leadership never even entertained the notion of dismantling the system. The Gulag was a pillar of the Soviet system, as important for its role in the battle to cleanse and shape the Soviet home front as for its role in military production.