Several anti-immigration politicians in Europe have been prosecuted for hate speech; some of these trials were highly mediatized. To what extent, and how, does hate speech prosecution of anti-immigration politicians affect voting for their party? We address this question by an experiment (N = 372) using manipulated versions of a television news story about a politician of the Dutch Party Forum for Democracy (FvD). We go beyond prior studies by disentangling the mechanisms driving the electoral ramifications of hate speech prosecution, assessing the moderating role of multiculturalist attitudes separately and in combination with six mediators (anti-establishment attitudes, issue salience immigration, perceived party’s effectiveness and legitimacy, support for free speech, and perceived party visibility). Among voters who are positive toward multiculturalism, exposure to a news story about prosecution boosts support for free speech and perceived visibility and support for the FvD. Both aspects are positively related to voting for FvD. This improves our understanding of the mechanisms of hate speech prosecution, informing public debates of how to react to controversial speech by politicians.