Free Speech and the Law of Evidence

To what extent does the First Amendment limit the ability of prosecutors to offer evidence of a defendant’s past protected speech? As it turns out, the Supreme Court has touched on this question in only a handful of rulings, each of which it crafted to target only the distinctive facts of the case at hand. Many lower courts, however, have distilled from these decisions a sweeping, admissibility-favoring constitutional rule. According to that rule, the First Amendment imposes no limit on prosecutorial use of past-speech evidence—no matter how prejudicial—so long as it meets the minimum standard of evidentiary relevance. This approach is misguided. To begin with, it finds no support in the Court’s past decisions, which in fact favor, rather than disfavor, a meaningful judicial role in evaluating the use of past-speech evidence. Even more important, a hands-off stance clashes with long-honored free-speech-supporting constitutional policies. As a result, this Article calls for judicial recognition of a new set of First Amendment protections that operate whenever challenged past-speech evidence involves expression on a matter of public concern. This build-out of existing doctrine comports with the Court’s specialized protection of public-concern speech in a wide variety of settings. It also gains momentum from the Court’s jurisprudence regarding constitutional review of generally applicable laws—in this case, the generally applicable law of evidence. On close examination, the doctrine in this field, and the policies that underlie it, provide strong support for an approach that imposes both procedural and substantive constraints on the use of public-concern speech to secure criminal convictions. Such an approach is offered here