This article sheds light on the debate regarding political trust and protest activity. The debate boils down to the question whether trust in politics is positively or negatively related to protest activity. We exploit a dataset encompassing data on about 9,000 demonstrators spread over seven European countries. These demonstrators' trust in their parliaments varies widely, ranging from trustworthy capable, to corrupt incapable. We examine the diverging sociodemographic profiles and motivational dynamics that turn distrusting and trusting citizens into demonstrators. We hypothesize and show that distrusting demonstrators turn their back to institutionalized politics; for them, demonstratingsubstitutesthe party politics they distrust. For trusting demonstrators, demonstratingsupplementsparty politics. Trusting and distrusting demonstrators also differ considerably in terms of motivation. Distrusting demonstrators are stronger motivated to demonstrate than trusting demonstrators. Moreover, while political cynicism amplifies the motivation of distrusting demonstrators, it suppresses the motivation of trusting demonstrators. We conclude that the question to be answered is not so much whether people who engage in protest activity trust or distrust their political elites, but rather who the trusting and distrusting protesters are and why they protest.