Ideological Polarization on the Supreme Court

Abstract

Judicial polarization is an important but underexplored aspect of judicial behavior. This analysis uses a gamut of measures to assess polarization on the Supreme Court across chief justice and jurisprudential regimes. I examine individual justice polarization and ideological extremity over full tenures on the Court and also how Court polarization is responsive to polarization in coordinate institutions. I find mixed evidence of greater polarization in the abortion rights regime. I find strong evidence of increasing Court polarization concomitant with congressional and presidential polarization since the 1950s across chief justice regimes. Court polarization is responsive to polarization in coordinate institutions. I do not find that individual justices become more polarized over time. Justices shift ideologically over their careers, and this shift is on average to the Left. These findings are robust across multiple specifications of the models and multiple alternative measurements, controlling for other factors which might influence polarization.