Public support for violent vigilantism remains underexplored in public opinion research, and traditional survey methods may be systematically distorted by social desirability bias. This study investigates whether social desirability bias suppresses reported support for vigilantism among Americans and whether emotions — particularly anger — predict respondents' tendencies to misreport. Using a list experiment in an online survey of 2,007 census-representative American adults, I estimate the true prevalence of support for vigilantism and compare to an item asking respondents to report support directly. Drawing on psychological evidence that anger may be a cue for truthfulness, I examine whether angrier respondents misreport less frequently.