During the Second World War, as the Soviet Red Army was locked in brutal combat against the Nazis, Joseph Stalin ended the state's violent, decades-long persecution of religion. In a stunning reversal, priests, imams, rabbis, and other religious elites—many of them newly-released from the Gulag—were tasked with rallying Soviet citizens to a "Holy War" against Hitler. To the delight of some citizens, and to the horror of others, Stalin's reversal encouraged a widespread perception that his "war on religion" was over. A revolution in Soviet religious life ensued: soldiers prayed on the battlefield, entire villages celebrated once-banned holidays, and state-backed religious leaders used their new positions not only to consolidate power over their communities, but also to petition for further religious freedoms. Offering a window on this wartime "religious revolution," God Save the USSR focuses on the Soviet Union's Muslims, using sources in several languages (including…