THE NARROW CONFINES OF INSTITUTIONAL ACTIVISM: THE U.S. SUPREME COURT, ABORTION, AND AMICUS CURIAE BRIEFS^*

Abortion disputes routinely occur in the judicial realm. Before the Supreme Court, from Roe to Dobbs, both reproductive rights and antiabortion movement groups and their allies engaged in institutional activism, filing amicus curiae (or friend-of-the-court) briefs to influence case outcomes. The number of such briefs has increased substantially over time. Yet few movement researchers investigate this form of institutional activism. We examine amicus briefs in over forty abortion cases from 1971 to 2022, discerning which amicus filers and frames influence justice voting, including for the pivotal moderate justices. We situate our work in resource mobilization, professional status, and framing theorizing, concluding that amicus briefs significantly shape judicial outcomes in abortion cases. However, our results show effective amicus strategies confront a narrow set of opportunities for judicial influence. Unsurprisingly, the Supreme Court battle over reproductive rights is heavily shaped by justice ideology, with filer and framing approaches—when they are influential—impacting mainly moderate justices.