It is often claimed that conspiracy theories are endorsed with the same level of intensity across the left-right ideological spectrum. But do liberals and conservatives in the United States embrace conspiratorial thinking to an equivalent degree? There are important historical, philosophical, and scientific reasons dating back to Richard Hofstadter’s book The Paranoid Style in American Politics to doubt this claim. In four large studies of U.S. adults (total N = 5049)—including national samples—we investigated the relationship between political ideology, measured in both symbolic and operational terms, and conspiratorial thinking in general. Results reveal that conservatives in the United States were not only more likely than liberals to endorse specific conspiracy theories, but they were also more likely to espouse conspiratorial worldviews in general (r =.27, 95% CI:.24,.30). Importantly, extreme conservatives were significantly more likely to engage in conspiratorial thinking than extreme liberals (Hedges’ g =.77, SE =.07, p <.001). The relationship between ideology and conspiratorial thinking was mediated by a strong distrust of officialdom and paranoid ideation, both of which were higher among conservatives, consistent with Hofstadter's account of the paranoid style in American politics.