Legitimacy theory suggests that judges are uniquely capable of increasing public support for government policies. However, this capacity may not be universal but conditional, depending on the institutional design of courts. In the United States, institutional differences between federal and state courts may make state judiciaries less capable of increasing public support for government policies. I investigate this possibility using an original survey experiment. Respondents were randomly assigned to one of three treatments, attributing the legalization of same-sex marriage to a state court, a governor, or a state legislature. I find, generally, that state courts are no more effective than other state institutions at building public support, but that this capacity of courts is variable, depending on levels of judicial independence.