We’ve been backing the proposition that the Erie doctrine concerning federal courts’ prediction of state law precludes courts clothed only with diversity jurisdiction from expanding state tort liability in novel ways since just about the beginning of the Blog.  However, our analyses have tended to be forward looking.  We typically start with the Supreme Court’s definitive statement in Day & Zimmerman, Inc. v. Challoner, 423 U.S. 3 (1975), that federal courts are “not free to engraft onto those state rules exceptions or modifications which may commend themselves to the federal court, but which have not commended themselves to the State in which the federal court sits.”  Id. at 4.  We then typically address ourselves to the law of circuit where the infraction arose.

Today, we’re mostly going in the opposite direction to discover the genesis of this principle, although we will keep an eye out for other United States Supreme Court precedent to the same effect.  Erie conservatism, of course, has its origins in the Supreme Court’s seminal directive in Erie Railroad Co. v. Tompkins, 304 U.S. 64 (1938) (Brandeis, J.), that, “[e]xcept in matters governed by the Federal Constitution or by Acts of Congress, the law to be applied in any case is the law of the State.”  Id. at 78.  Erie condemned federal courts’ disregard of state law “which is often little less than what the judge advancing the doctrine thinks at the time should be the general law on a particular subject.”  Id.  Federal judges may not “brush[] aside the law of a state in conflict with their views.”  Id.

Expressing core constitutional principles of federalism, the Court in Erie declared that “no clause in the Constitution purports to confer . . . power upon the federal courts” to “declare substantive rules of common law applicable in a state.”  Id. at 78.  When a federal court “declare[s]” a substantive rule of state law not firmly anchored in clear state legislative or decisional authority, it “invade[s] rights which . . . are reserved by the Constitution to the several States” and engages in “an unconstitutional assumption of [state] powers.”  Id. at 79-80.  Erie thus restored the States’ prerogative to “define the nature and extent” of a litigant’s rights, an “object [that] would be thwarted if the federal courts were free to choose their own rules of decision whenever the highest court of the [S]tate has not spoken.” West v. AT&T Co., 311 U.S. 223, 236 (1940).

Subsequent high court decisions have recognized that “Erie was deeply rooted in notions of federalism.”  Boyle v. United Technologies Corp., 487 U.S. 500, 517 (1988).  Erie sought to achieve, or at least shoot for, “twin aims”:  “‘discouragement of forum-shopping and avoidance of inequitable administration of the laws[.]’” Salve Regina College v. Russell, 499 U.S. 225, 234 (1991) (quoting Hanna v. Plumer, 380 U.S. 460, 468 (1965)).  The comity between the respective powers of the states and federal courts that Erie required was “fundamental to our system of federalism.”  Johnson v. Fankell, 520 U.S. 911, 916 (1997).  Erie principles thus prohibit “federal judges” from “displac[ing] the state law that would ordinarily govern with their own rules of federal common law.”  Boyle, 487 U.S. at 517.  Thus, “a federal court is not free to apply a different rule however desirable it may believe it to be, and even though it may think that the state Supreme Court may establish a different rule in some future litigation.”  Hicks v. Feiock, 485 U.S. 624, 630 n.3 (1988).

This intent to preserve our system of federalism should inform a federal court’s Erie analysis.  When a state’s highest court has decided the issue at hand, its ruling “is to be accepted by federal courts as defining state law.”  West, 311 U.S. at 236.  When that has not occurred, “[t]he proper function” of a federal court “is to ascertain what the state law is, not what it ought to be.”  Klaxon Co. v. Stentor Electric Manufacturing Co., 313 U.S. 487, 497 (1941).  “[I]t is the duty of the [federal judge] in every case to ascertain from all the available data what the state law is and apply it rather than to prescribe a different rule, however superior it may appear.”  West, 311 U.S. at 237.  Diversity jurisdiction “does not carry with it generation of rules of substantive law.”  Gasperini v. Center for Humanities, Inc., 518 U.S. 415, 426 (1996).

As the above discussion demonstrates, while the Supreme Court’s admonition in Day & Zimmerman against federal courts “engraft[ing]” novel liability onto existing state tort law is the most direct statement of Erie-based conservatism with respect to state law, it is not the only – or even the most recent – expression of this principle.  The doctrine did not arise, full-blown, in Day & Zimmerman, like Athena springing from the head of Zeus.  Rather, the principle of Erie conservatism has strong and deep roots in the Court’s Erie jurisprudence, that reach back to Erie v. Tompkins itself.