While extant research has documented the existence of negative attitudes toward Muslim Americans, it is unclear whether old-fashioned racism (OFR) is at the root of contemporary Islamophobia, and whether beliefs in the inherent inferiority of Muslims are linked to support for political actors and policies that aim to further isolate them. Bringing to bear a unique dataset of 1,044 white, black, Latino, and Asian participants, we demonstrate that a nontrivial portion of survey respondents make blatantly racist evaluations and rate Muslim Americans as the least “evolved” group. Next, we illustrate that these dehumanizing attitudes are strongly linked to modern objections of Muslim Americans, which we measure with a new Muslim American resentment scale (MAR). Our mediation analysis reveals that the relationship between OFR, support for President Trump, and various policy positions is powerfully mediated by MAR. These results suggest that the relevance of OFR in contemporary politics should not easily be dismissed, and that the literature on racial attitudes, which has predominantly focused on the Black-white dichotomy, should also be extended to appraisals of Muslim Americans.