September 23, 2026
How can you tell where someone is “from”? Historically, an individual’s national identity was singular, starting with formal nationality. One’s national center of gravity was readily determinable. Not so today. Determining one’s primary national identification is no longer an easy thing in many cases. This is consequentially enabled by the growing acceptance of dual citizenship. One can openly identify as a formal member of more than one country in a way that was disfavored in the past.
International investment law, however, has not caught up to this reality. In an increasing number of international arbitrations, tribunals are shutting the doors on dual national claimants under the doctrine of “dominant and effective nationality.” The test, which requires arbitrators to determine to which of two nationalities a claimant is more strongly attached, works from antiquated conceptions of nationality as essentially singular. Contemporary sociological conditions now allow for fluid and non-zero-sum national associations. Moreover, application of the dominant nationality test will have unintended consequences. It may revive an imperial era practice in which investors from the Global North carefully nurture their homeland citizenship even while they establish themselves permanently as non-citizens, alongside their investments, in states of the Global South.
For better or worse, citizenship’s place in the world has been transformed. International investment law has been generally slow to absorb change, siloed from scholarship outside the perimeter of specialized arbitration journals. The nature of international arbitration, moreover, systemically inclines it to putative doctrinal regularity. Here as in other areas tribunals should come to incorporate elements of global social meanings into their decision-making presumptions. This Article brings citizenship theory to bear on a field that is systemically insulated from exogenous bodies of scholarship.
The “dominant and effective nationality” doctrine has become increasingly difficult to apply in modern investment disputes. The doctrine developed at a time when dual nationality was relatively uncommon and one nationality could often be treated as more meaningful than the other. Today, however, individuals may have genuine personal, family, economic, and political ties to more than one country, making that kind of comparison much less straightforward.
The problem is illustrated by Ballantine v. Dominican Republic. The U.S.-born claimants retained significant ties to the United States after moving to and naturalizing in the Dominican Republic. Nevertheless, the arbitral tribunal found that their Dominican nationality was dominant and barred their claims under CAFTA-DR. The case demonstrates how a doctrine designed for an earlier conception of citizenship can produce substantial consequences for modern dual nationals.
The dominant-nationality test may also create unintended incentives for investors. Investors who want to preserve treaty protections may be discouraged from becoming citizens of the countries where they live and invest, or may structure their citizenship status with potential future claims in mind. Rather than preventing strategic nationality choices, the test may therefore encourage them.
International investment law, Spiro argues, should better reflect the reality of modern dual citizenship. His Article challenges the assumption that one nationality must always prevail over another and calls for a framework that better accounts for meaningful ties to more than one country.
Read the full Article here.
Bio: Professor Peter J. Spiro is the Charles R. Weiner Chair in International Law at Temple University Beasley School of Law, where he specializes in international, immigration, and constitutional law. Before entering academia, Professor Spiro also served on the National Security Council staff and as an attorney-adviser in the U.S. Department of State’s Office of the Legal Adviser.