Party politics in contemporary Europe is changing. New parties with anti-establishment appeals, often playing on their novelty and using the anti-corruption card, have achieved notable electoral successes in recent times in both Western and Central and Eastern Europe. Moreover, radical right parties have performed well at the ballot box in some countries, but not in all. Bringing together junior and more senior scholars from both sides of the Atlantic this panel seeks not only to explain the power of anti-establishment appeals, their longevity and effect on the strategies of mainstream parties, but also to examine more broadly what drives party politics in contemporary Europe: why some party systems are more stable than others and why some parties prove to be “annuals” in the political garden, but others prove to be “hardy perennials”. Furthermore, the panel assesses the impact of the national party system’s structure and stability on parties’ choices in the European Parliament: whether to co-operate with transnational party groups and with whom.