Abstract This article explains Europarties' inability to act and position themselves cohesively in EU politics. It develops a theoretical framework based mainly on domestic parties' disincentives to agree on a common Europarty position. The framework is applied to the case of social democracy and fiscal competition. Despite opportunity for agreement, (dis)incentives related to self-economic interests and domestic institutional settlements (and corresponding electoral calculuses) were aggravated by substantive ideological preferences. The case implications are drawn on literatures on the national parties' general positioning on EU issues as well as on Europarties and the EU agenda.