How do political outsiders in autocratic legislatures use institutional authorities? I argue that legislative authorities tailored to offering constituency service help to level the playing field between regime and opposition candidates competing for the crucial resource of public support. Though regime candidates may have the ear of those in power through backdoor channels and personal connections, opposition politicians can use ‘by the book’ politics – the legitimate authorities that accompany their office – to supply the constituency goods voters expect. I construct a database of activity from recent legislative terms in Morocco, including more than 27,000 unique queries submitted by elected members of parliament to government ministers, and find systematic evidence that voters reward parties and MPs that engage in more constituency service via institutionalized action. Yet the relationship between activity and voteshare is exclusive to opposition parties: regime-linked parties do not see electoral gains from increased legislative activity, but neither are they punished for shirking in office.