We measure how a network of heroes can legitimize and diffuse extreme political behaviors. We exploit newly declassified intelligence files, novel voting data, and regimental histories to show that home municipalities of French line regiments arbitrarily rotated under Philippe Petain's generalship through the heroic World War I battlefield of Verdun diverge politically thereafter, particularly following Petain's own overt espousal of authoritarian views. Further, under Petain's collaborationist Vichy regime (1940–1944), they raise 7 percent more active Nazi collaborators per capita. These effects extend across all forms of Nazi collaboration and diffuse beyond the veterans themselves.