This necessitates studying the development of the European Parliament (EP) and the role of political parties comprising the supranational party system of the European Union, ensuring decision-making, and legitimising these decisions based on interest representation.
Structural and functional features of EuropartiesKey agents of political process taking place in the European Parliament are political groups consisting of European-level parties (Europarties)1 . Europarties are umbrella organisations bringing together national parties committed to a common ideology and political programme [14]. Individual membership in Europarties is also possible for members of national parliaments and the EP.During EP elections, voters elect only national parties -some the of them constitute Europarties, others act without the support of the latter. National parties compete for votes allocated to each country within the national apportionment of MEP seats. Thus, election campaigns focus primarily on national agendas [15].Europarties are financed by the EU funds and private donations. They have the right to campaign at European level 2 . Funds are allocated in line with the objectives stated in the political programmes of Europarties.A key characteristic of Europarties is their two-tier structure, which includes national and supranational components. National parties serve as channels for recruiting members of the political elite, who interact with electoral groups in EU member states through representing their interests. Further, national parties set up Europarties, which influence the formation of coalitions and the functioning of the EU governing bodies.This particularity is a result of the conditions, in which Europarties develop in the EU -an intergovernmental association, which has created a system of supranational coordinating and governing institutions. In this sense, the European Parliament -as well as the European-level partybuilding process -is of a partly artificial nature. Its emergence was not a result of political struggle and its gradual institutionalisation, which shaped modern institutions of parliamentarism and political parties. It is a product of agreements between states and political elites, a result of 'political engineering' at the supranational level [6; 10]. Thus, the question of long-term stability and independence of supranational EU institutions remains relevant.Increasing international integration requires securing its legitimacy from citizens of European countries, which necessitated the transition to direct EP