In the decades following the Revolution, the supernatural exploded across the American landscape—fabulous reports of healings, exorcisms, magic, and angels crossed the nation. Under First Amendment protections, new sects based on such miracles proliferated. At the same time, Enlightenment philosophers and American founders explicitly denied the possibility of supernatural events, dismissing them as deliberate falsehoods—and, therefore, efforts to suborn the state. Many feared that belief in the supernatural itself was a danger to democracy. In this way, miracles became a political problem and prompted violent responses in the religious communities of Prophetstown, Turtle Creek, and Nauvoo. In Blood from the Sky, Adam Jortner argues that the astonishing breadth and extent of American miracles and supernaturalism following American independence derived from Enlightenment ideas about proof and sensory evidence, offering a chance at certain belief in an uncertain religious climate. Jortner breaks new ground in explaining the rise of radical religion in antebellum America, revisiting questions of disenchantment, modernity, and religious belief in a history of astounding events that—as the early Americans would have said—needed to be seen to be believed.