Counterclaims in International Law

Counterclaims are claims raised by respondents. Various international courts and tribunals have expressed their jurisdiction to hear counterclaims as an emanation of their inherent powers, even though their constitutive instruments are silent. Modern rules of court often contain provisions on counterclaims. So do the principal instruments and rules regulating international investment arbitration and international commercial arbitration. Counterclaims allow a tribunal to streamline and simplify the settlement of complex international disputes, where parties each present claims related to the same underlying dispute. However, respondent States may opportunistically squeeze tenuously related ‘counterclaims’ within the ambit of the jurisdiction established over the principal claim. This chapter addresses the role of counterclaims before the ICJ and international investment arbitration tribunals.