Despite the importance and neutrality of constitutional rights, empirical research suggests that ideological inclinations unduly affect their assessment and application. In this study, we conducted two experiments in order to investigate the nature of the ideological bias in a constitutionally relevant decision (right-to-demonstration), and how to mitigate it. We find that ideological bias is driven by in-group favoritism. In addition, we find that prior commitment, through a signed declaration, to be impartial or to prioritize constitutional rights encourages participants not to disfavor out-groups. On the other hand, we do not find evidence that using a temporary blinding procedure mitigates the ideological bias.