The effectiveness of tracks of diplomacy strategies in third-party interventions

International mediation is not conducted solely by official actors such as states or international organizations. Non-official parties such as individuals and non-governmental organizations increasingly intervene as third-party mediators in conflicts. Both official and unofficial interventions are conceptualized as tracks of diplomacy (ToDs). Even though there is a vast quantitative literature on international mediation, most studies focusing on ToDs have been qualitative and produced few generalizable insights. This article extends the existing literature on third-party intervention by developing a theoretical model to explain the effectiveness of different ToDs, which is then empirically tested in a first large-N study. The findings indicate that the leverage and resources of ToDs determine outcome effectiveness. Track One Diplomacy, that is, efforts by official actors, tends to be the most effective form of intervention as greater leverage and more resources invested can make track intervention more effective. It is also found that combined mediation efforts of both official and unofficial tracks can be more effective than independent track actions. Since conflicts with mediation are unlikely to be a randomly selected set, a selection estimator is used to test the hypotheses on effectiveness. The empirical findings support the theory and demonstrate that the specific type of mediating actor seems highly important.