Third-party Interventions before Both the ECtHR and the CJEU

Third parties’ interventions are regulated differently before the European Court of Human Rights (ECtHR) and the Court of Justice of the European Union (CJEU). This chapter first summarises the different regimes that govern third parties’ participation in each court in light of recent developments, noting significant differences. While civil society organisations increasingly file interventions before the ECtHR, the most critical procedure before the CJEU does not admit interventions by private parties but only by the Member States’ governments and EU institutions. The chapter then reflects on whether the rules of the two Courts are appropriate to guarantee adequate access and representation of the diverse interests affected by the case. In the international and supranational context, we should pay particular attention to whether the regulatory frameworks governing third-party interventions can give voice to under-represented minorities, thus counteracting the risk of a pro-state or majoritarian bias.