U.S. immigration policy at the court: organized interests & asymmetric decisions

Do some interest groups fare better on immigration cases before the Supreme Court? We build on interest group power theory and extend the literature by focusing on the heterogeneity of signers to amicus curiae briefs. Specifically, we argue that the presence of organizations that collaborate with multiple communities sends stronger signals to the justices. We use network community detection methods to reveal the coalition behavior of amici that file briefs on immigration cases between 1947 and 2021. We find that immigration cases garner far more amici on the liberal than conservative side, and that amici coalition behavior varies from acting alone, to cliques, to multiple communities. The presence of an amicus that works in multiple communities has a significant and asymmetric effect on judicial decision-making, such that conservative amici move justices to decide in their favor, but there is no comparable effect for liberal groups. Moreover, the effect is conditional on justice ideology, with moderate justices moving to side with conservative amici. In the domain of immigration cases, the accent heard by justices is that of the conservative side.