Pan-European parties as alliances of national parties are intended to develop into a pillar of pan-European democracy. National conservatives, conservatives, social democrats, liberals, greens, the left, and opponents of Europe have come together in the European Parliament to form factions. But are these European parties truly more than a loose alliance and a theoretical construct? What dynamics can they develop - and how resilient are they? Historian and European law expert Otto Markus Carstens seeks answers in the party statute of the EU and in the organizational forms of the existing European parties. He provides an overview of the parties and their respective working methods in the European Parliament. Of central importance is the manner and extent to which European parties actually influence decision-making processes within the European Union. Carstens, who has gained personal experience as a staff member of the European Parliament and as a local politician, identifies both opportunities and obstacles for European parties and their representatives.