Does Legal Doctrine Matter? Unpacking Law and Policy Preferences on the U.S. Supreme Court

TLDR

Judicial scholars struggle to separate the influence of law and policy on U.S. Supreme Court decisions. The study introduces a novel method to measure the effect of law on justices’ rulings. The authors use congressional and presidential positions on Supreme Court cases to isolate policy from legal factors, enabling the identification of three doctrines—precedent adherence, judicial restraint, and strict First Amendment speech protection—in their analysis.

Abstract

Judicial scholars often struggle to disentangle the effects of law and policy preferences on U.S. Supreme Court decision making. We employ a new approach to measuring the effect—if any—of the law on justices' decisions. We use positions taken on Supreme Court cases by members of Congress and presidents to identify policy components of voting. Doing so enables us to isolate the effects of three legal doctrines: adherence to precedent, judicial restraint, and a strict interpretation of the First Amendment's protection of speech clause. We find considerable evidence that legal factors play an important role in Supreme Court decision making. We also find that the effect of legal factors varies across justices.