The New Impartial Jury Mandate

Impartiality is the cornerstone of the Constitution’s jury trial protections. Courts have historically treated impartiality as procedural in nature, meaning that the Constitution requires certain prophylactic procedures that secure a jury that is more likely to reach verdicts impartially. But in Peña- Rodriguez v. Colorado, 137 S. Ct. 855 (2017), the Supreme Court recognized for the first time an enforceable, substantive component to the mandate. There, the Court held that criminal litigants have a Sixth Amendment right to jury decisions made without reliance on extreme bias, specifically on the basis of race or national origin. The Court did not provide a standard for determining when evidence of partiality is sufficient to set aside a verdict but made clear that an otherwise procedurally adequate decision may fall to substantive deficiencies. This Article advances a structural theory of the Constitution’s impartial jury mandate, focusing on the interplay between its ex ante procedural and ex post substantive components. The Article argues that the mandate has traditionally taken shape as a collection of procedural guarantees because of a common law prohibition on reviewing the substance of jury deliberations. Peña-Rodriguez tosses this constraint, allowing judges for the first time to review the rationales upon which jurors base their verdicts. The Article then offers a novel approach for applying substantive impartiality more broadly by looking to the Equal Protection Clause’s tiers of scrutiny. It concludes that ex ante procedural rules and ex post substantive review can operate in conjunction to tease out undesirable, impermissible forms of jury bias, while still allowing for desirable, permissible forms of jury bias.