Politics from the Bench? Ideology and Strategic Voting in the U.S. Supreme Court

Supreme Court justices often vote along ideological lines. Is this due to a genuinely different interpretation of the law, or does it reflect justices' desire to resolve politically charged legal questions in accordance with their personal views? To learn more about the nature of decision-making in the Court, we differentiate between votes that were pivotal and those that were not. When a justice's choice decides the outcome of a case, her ideology plays an even greater role in determining her vote - both relative to her choices on other cases and relative to other justices voting on the same case. We develop and empirically assess a model of voting in which judges trade off expressive and instrumental concerns. The evidence we present suggests that justices vote strategically, at least in part, to affect precedent.