Brusselss idea of a wider Europe implies that Europeanisation is not limited to EU member states. The EU can, so it claims, also exert impact beyond its borders. One of the channels of external EU influence is cooperation between Europarties and parties outside the Union. Through mutual visits and joint activities, non-EU parties become internationally socialised, i.e., are exposed to the Europarties norms as well as values, and experience the rules as well as practices that shape European party-building. What are the incentives for Europarties and non-EU parties to cooperate with each other?...