Intersystemic Statutory Interpretation: Methodology as ‘Law’ and the Erie Doctrine

Do the Erie Doctrine and its “reverse-Erie” mirror require state and federalcourts to apply one another’s statutory interpretation methodologies when they interpret one another’s statutes? Surprisingly, the courts have no consistent answer to this question—even though state and federal courts constantly interpret one another’s laws. What’s more, exploring this application of Erie reveals that one of the most important jurisprudential questions about statutory interpretation also remains entirely unresolved: namely, are the rules of statutory interpretation “law,” individual judicial philosophy, or something in between?\nThis Article argues that many federal courts are getting the Erie question wrong—or at least that they are unaware that the question exists in the first place. The Erie inquiry also makes clear that federal courts treat both state and federal statutory interpretation methodology as much less “lawlike” than they treat analogous interpretive principles, without acknowledging or justifying the distinction. Federal courts routinely bypass state interpretive principles when they interpret state statutes, but almost always look to other state methodological principles, including state rules of contract interpretation, choice of law, and constitutional interpretation. Further, unlike in those other areas, the U.S. Supreme Court does not treat even its own statements about federal statutory interpretation principles as “law” and does not give themprecedential effect. This practice has licensed an interpretive freedom for state and lower federal courts when those courts interpret federal statutes—a freedom that facilitates federal-law disuniformity that the Court generally does not tolerate in other contexts. This Article challenges the notion that statutory interpretation is sufficiently different from other decisionmaking regimes to justify these distinctions.