The development of constitutional limitations on choice of law by the United States Supreme Court has turned primarily on the due process clause and the full faith and credit clause of the United States Constitution. In theory at least, each constitutional provision rests upon separate grounds. The full faith and credit clause, as it applies to public acts, would compel a forum state under appropriate circumstances to honor the sovereignty of a foreign state in the federal system and to apply the law of the foreign state whose interests are sufficiently compelling. The due process clause limits the power of a state to give extraterritorial effect to its own laws in a manner which is unfair or unreasonable, given the relationship between that state, the parties, and the transaction being sued upon.
W. C. Williams Jr.,
The Impact of Allstate Insurance Co. v. Hague on Constitutional Limitations on Choice of Law,
U. Rich. L. Rev.
Available at: http://scholarship.richmond.edu/lawreview/vol17/iss3/3