Also known as: federal rules of decision · rule of decision
Written by attorneys · grounded in primary & secondary sources — see below
A substantive legal standard drawn from federal statutes, federal common law, or the Constitution that federal courts apply to resolve a claim or defense. Federal law supplies this rule when the claim arises under federal law or implicates uniquely federal interests that require uniformity. In contrast, state law supplies the rule of decision in a civil case when the claim or defense is governed by state substantive law.
Frederick Ferguson sued his former employer in federal court under state-law contract claims after removal on diversity grounds. He sought to call his elderly neighbor as a witness, but the neighbor had been placed under a state conservatorship for cognitive impairment. The court applied the state rule rendering the neighbor incompetent because state law supplied the rule of decision on the contract claims.
Farid Farahani, a corporate officer, faced a federal securities enforcement action in district court. He withheld an email to outside counsel that discussed both business strategy and legal compliance. The court applied federal common law to determine whether the communication was privileged because federal law supplied the rule of decision on the securities claims.
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Faye Fuller sued her landlord in federal court on state-law breach of lease claims after water damage to her servers. The landlord introduced a notarized acceptance certificate that, under state law, created a presumption shifting the burden of persuasion on the condition of the premises. The court applied the state presumption because state law supplied the rule of decision.
Faith Fitzgerald, a foreign national, sued a foreign official in federal court under the Alien Tort Statute for alleged abduction and torture abroad. The court looked to federal common law to determine whether the claim stated a viable cause of action because the statute invoked uniquely federal interests in enforcing the law of nations.
Farah Fox, a medical provider, filed a class action in federal court against an insurer under state law for unpaid claims. State law barred class actions for the type of relief sought. The court applied the federal class action rule because it regulated procedure and did not abridge any substantive right supplied by state law.
Fernando Farrell's union sued his employer in federal court under section 301 of the Labor Management Relations Act to enforce a collective bargaining agreement. The court applied federal common law to interpret the agreement because Congress had authorized federal courts to develop substantive rules for such contracts.
State law supplies the rule of decision on a claim or defense when the claim arises under state substantive law, such as in a diversity action or a supplemental state-law claim. Federal rules of evidence then direct courts to apply state law on issues like witness competency, privilege, and the effect of presumptions.
Supporting sources
No. When federal law supplies the rule of decision on the primary claims, federal common law governs privilege for the entire action even if supplemental state claims are also present. State privilege rules apply only to the state-law claims standing alone.
Supporting sources
A federal court may fashion a federal rule of decision when a federal interest requires uniformity and state law would frustrate federal policy. The court considers relevant policies, equity, analogous rules, and scholarly sources, or it may borrow state law if doing so serves the federal purpose without undermining federal objectives.
…standard that forbids any award that "deviates materially from what would be reasonable compensation," ibid. , is a substantive rule of decision that federal courts must apply in diversity cases governed by New York law. I recognize that state rules of appellate procedure do not necessarily bind federal appellate courts. The…