The Constraining Capacity of Legal Doctrine on the U.S. Supreme Court

TLDR

Law’s influence on Supreme Court decisions is contested, with attitudinal models emphasizing ideology and hybrid models proposing independent effects of law and ideology. The study proposes a new conceptualization of legal constraint that links the degree of legal discretion to the strength of ideological influence on justices’ votes. The authors develop theoretical models of strict, intermediate, and rational basis scrutiny and test them using a multilevel framework on the Grayned free‑expression doctrine. Strict scrutiny significantly constrains ideological voting, whereas intermediate scrutiny and lower levels promote high ideological voting.

Abstract

Does law exhibit a significant constraint on Supreme Court justices' decisions? Although proponents of the attitudinal model argue that ideology predominantly influences justices' choices, “hybrid models” posit that law and ideology exhibit discrete and concurrent effects on justices' choices. I offer a new conceptualization of legal constraint examining how legal rules permit varying degrees of ideological discretion, which establishes how strongly ideological preferences will influence justices' votes. In examining the levels-of-scrutiny legal doctrine, I posit theoretical models highlighting the differential constraining capacities of the strict scrutiny, intermediate scrutiny, and rational basis rules. I use a multilevel modeling framework to test the hypotheses within the context of the Grayned doctrine in free expression law. The results show that strict scrutiny, which Grayned applied to content-based regulations of expression, significantly constrains ideological voting, whereas intermediate scrutiny (applied to content-neutral regulations) and the low scrutiny categories each promote high levels of ideological voting.