We study how campaign contributions aect the voting strategies and effectiveness of justices in the Supreme Court of eight US states. A judge's voting strategy leans more heavily towards an interest group the larger are its contributions to the judge, and the smaller are its contributions to other members of the court. This panel effect is consistent with an equilibrium response to contributions to other members of the court. Observed contributions have a large effect on the decisions and effectiveness of individual judges, but tend to counterbalance each other, producing a small effect on the decisions and effectiveness of the Court.
R&R Rand Journal of Economics