In Swift v. Tyson, Justice Story argued that federalization of the law of negotiable instruments was necessary to thwart local courts from adopting rules that favored local interests at the expense of national welfare. Variations of this argument have been embraced by modern proponents of federalizing many aspects of international law, including customary international law. The argument proves too much, and fails to take account conditions where local decisionmakers have an incentive to reach globally optimal outcomes. The law of negotiable instruments illustrates this point: State law now occupies this field but, contrary to Story's concern, the law in the United States is uniform and stable. Two international conventions currently under negotiation, the Hague Child Support Convention and the UNCITRAL Electronic Commerce Convention, provide further examples of cooperation without mandatory federal oversight.

Paul B. Stephan, What Story Got Wrong: Federalism, Localist Opportunism and International Law, 73 Missouri Law Review, 1041–1061 (2008).