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Horizontal Erie and the Presumption of Forum Law
109 Michigan Law Review 1237-1291 (2011)
  • Michael Steven Green, William & Mary Law School
According to Erie Railroad v. Tompkins and its progeny, a federalcourt interpreting state law must decide as the state’s supremecourt would. In this Article, I argue that a state court interpretingthe law of a sister state is subject to the same obligation. It mustdecide as the sister state’s supreme court would. Horizontal Erie is such a plausible idea that one might think it isalready established law. But the Supreme Court has in fact givenstate courts significant freedom to misinterpret sister-state law. Andstate courts have taken advantage of this freedom, by routinely presumingthat the law of a sister state is the same as their own—oftenin the face of substantial evidence that the sister state’s supremecourt would decide differently. This presumption of similarity to forumlaw is particularly significant in nationwide class actions. Aclass will be certified, despite the fact that many states’ laws applyto the plaintiffs’ actions, on the ground that the defendant has failedto provide enough evidence to overcome the presumption that sisterstates’ laws are the same as the forum’s. I argue that this vestige ofSwift v. Tyson needs to end. Applying horizontal Erie to state courts is also essential to preservingfederal courts’ obligations under vertical Erie. If New York statecourts presume that unsettled Pennsylvania law is the same as theirown while federal courts in New York do their best to decide as thePennsylvania Supreme Court would, the result will be the forumshopping and inequitable administration of the laws that are forbiddenunder Erie and its progeny. As a result, federal courts haveoften held that they too must employ the presumption of similarityto forum-state law, despite its conflict with their obligations undervertical Erie. Applying horizontal Erie to state courts solves thispuzzle.
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Michael Steven Green. "Horizontal Erie and the Presumption of Forum Law" 109 Michigan Law Review 1237-1291 (2011) (2011)
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