This article assesses the top-down Europeanization of national political parties by the political groups of the European Parliament. Based on the premise that the national political parties alter their agendas and argumentation because of ties to their respective European Parliament political groups, the paper presents a case study of Latvia in the period from 2004 to 2019. The analysis focuses on the agendas of three political parties whose continuity can be clearly traced during the fifteen years – the “New Unity”, the “National Alliance” and the “Latvian Russian Union”. It concludes that the small number of members of the European Parliament elected from Latvia, migration of individual politicians from party to party, and low durability of Latvian parties themselves has limited the sustainability of Europeanization and impeded downloading of EU topics and principles to the national party level. Meanwhile, party programs of all three observed parties have Europeanized since 2004 in terms of the number and depth of the EU issues addressed.