Law's Dark Matter

43 Pages Posted: 25 Jun 2012 Last revised: 13 Nov 2023

Date Written: June 25, 2012


A state’s legal rules have extrajurisdictional effect if they are intended to be used in other court systems. Extrajurisdictional effect is puzzling because, absent certification, the courts of the state whose rules are at issue have no occasion to discuss it. They have reason to speak only about which rules they are obligated to follow. What the courts of other jurisdictions should do will be faced only by those courts. Unless questions of extrajurisdictional effect are certified to the relevant state’s supreme court, they will be discussed only by courts that are not in a position to provide authoritative answers. This gives a misty and jurisprudential aura to what is in fact a straightforward question of state law.

An example is the disagreement between advocates of Swift v. Tyson and Erie Railroad v. Tompkins. Although this appeared to be a jurisprudential debate between natural law theorists and positivists, it was in fact a disagreement about state law – in particular, whether a state supreme court intended its decisions concerning the common law to bind federal and sister state courts when adjudicating events occurring within the state. Had certification been possible, the disagreement could have been quickly resolved.

Because questions of extrajurisdictional effect have not gone away, neither has the conflict between Swift and Erie. One example concerns the law of choice of law. There is currently a debate about whether a state’s choice-of-law rules should be respected by federal and sister state courts when determining the territorial scope of the state’s laws. Here too the participants have treated the disagreement as jurisprudential, when it is in fact about a question of state law. As a result, a simple solution has been ignored – certification to the relevant state supreme court. The consequence of such certification, I argue, will be a vindication of Swift over Erie.

Keywords: Erie, Swift v. Tyson, Positivism, Choice of Law, Conflict of Laws, Renvoi, General Common Law

Suggested Citation

Green, Michael S., Law's Dark Matter (June 25, 2012). 54 William & Mary Law Review 845-84 (2013) , William & Mary Law School Research Paper No. 09-219, Available at SSRN:

Michael S. Green (Contact Author)

William & Mary Law School ( email )

South Henry Street
P.O. Box 8795
Williamsburg, VA 23187-8795
United States
(757) 221-7746 (Phone)

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