This essay examines Jack London’s 1910 short story “The Unparalleled Invasion” as a fantasy of racist nationalism (borrowing from his earlier “Yellow Peril” report from the Russo-Japanese War). London, like other American progressives of the early 20th century, looked to the emerging science of genetics and its implications for eugenicist technologies, finding both a frightening futuristic vision of race war fought by reproduction and a modestly consoling “scientific” defense of white supremacy.