The Influence of National Parliaments over Domestic European Union Policies Shirin Ahlbäck Öberg* and Ann-Cathrine Jungar This article presents survey results on Swedish and Finnish parliamentarians’ perceptions con- cerning their influence over domestic decision making in European Union (EU) matters. In the literature the parliaments in Sweden and Finland are classified as powerful ones that can exert considerable influence over domestic EU policy making. Moreover, Finland and Sweden joined the EU at the same time. Therefore the overall expectation is that the parliaments should be equally powerful. However, the results from this survey indicate a significant difference in perceived influence between the two parliaments. It is obvious that Swedish parliamentarians perceive themselves as more marginalised in relation to the government than Finnish parlia- mentarians. After trying different explanations, it is concluded that the differences can be ascribed to the parliaments’ different organisational set-ups for government oversight. Introduction The Europeanisation of National Parliaments When national parliaments make the decision to join the European Union (EU), and subsequently ratify treaty revisions, the result is a transfer of power to European political institutions. It has been suggested that national parliaments by ratifying deeper European integration are paradoxically the political institutions that lose the most power (Moravscik 1994). The reason for this deprivation of power is that parliaments delegate their decision- making competence to the national executives that negotiate and decide on their behalf on issues that are resolved within the EU. On top of this theory of power centralisation at the national level, there is an ongoing discussion within political science about the capacity of national parliaments to influ- ence decision making in general; internationalisation is a further constraint on their influence (Bryce 1921; Damgaard 1992). Nevertheless, national parliaments are still the main providers of democratic legitimacy to the EU, * Shirin Ahlbäck Öberg, Department of Government, P O Box 514, 751 20 Uppsala, Sweden. E-mail: shirin.ahlback@statsvet.uu.se ISSN 0080–6757 Doi: 10.1111/j.1467-9477.2008.00231.x © 2009 The Author(s) Journal compilation © 2009 Nordic Political Science Association Scandinavian Political Studies,Vol. 32 – No. 4, 2009 359