Political parties have generally been disregarded in the literature on political obligation. In this article I argue that, regardless of whether ordinary citizens or residents of a polity have any political obligations, partisanship generates its own kind of political obligations. Participating in party politics qua party members, supporters, activists or even mere voters produces benefits that generate corresponding and proportionate political obligations for those who enjoy them. The political obligations of partisans are easier to justify than those of ordinary citizens as the conditions under which the benefits of partisanship can be rendered excludable are easier to obtain.