The Substance/Substance Distinction
As “Easy Erie” suggests, the Erie doctrine is applied without substantial difficulty in most diversity cases. Erie and the Rules of Decision Act (RDA) require the federal court to apply state law, and the court does. It uses the state rules governing the standard of care to a trespasser, enforceability of contracts, the validity of wills and property transfers, and myriad other state rules of law, whether pronounced by statute or by common law.