Litigation in the European Court of Justice: Lawyers' influence on supranational decision-making

This paper assesses how private litigants’ propensity to win cases before international courts is conditioned by the quality of their legal counsel and by the constraints of intergovernmental politics. Building on legal mobilization and party capability theories, we argue that quality legal counsel bolsters a private party’s capacity to convey legal information to judges that is relevant to deciding the case in their favor. At the same time, we build on intergovernmentalist theories of international adjudication positing that judges will also be sensitive to political signals by national governments. As a result, we hypothesize that the influence of quality legal counsel on international judges is conditioned by the political support that member states' express. To assess these claims, we exploit an original dataset of parties and lawyers involved in disputes before the European Court of Justice (ECJ) – arguably the most successful and influential international court procuring access to private litigants. We find being represented by a lawyer bolsters the probability that litigants submit observations and win cases before the ECJ, yet this effect is the highest in the minority of cases where a majority of more member state governments intervene in favor of the applicant. We conclude by highlighting the necessity of combining theories of legal mobilization and intergovernmental politics in order to explain judicial decision-making in international courts.