The Human Rights Defence in International Investment Arbitration: Exploring the Limits of Systemic Integration

In a variety of investment arbitration cases, respondent States have argued that measures impugned by investors were mandated by that State's human rights obligations. Tribunals have generally been reluctant to engage with such arguments and to interpret the relationship between investment law and human rights in a straightforward manner. This article discusses two other possibilities: harmonious interpretation and prioritization. Harmonious interpretation seeks to read provisions from investment treaties and human rights treaties together, whereas prioritization gives normative superiority to one provision over another. We conclude that harmonious interpretation is facilitated by the discretionary character of common treaty standards in both human rights and investment law, but that the final result is unlikely to be very different from prioritization, because even harmonious interpretation requires that one provision is read in the light of, and thereby subjugated to, the other.