The Watchdogs of Subsidiarity: National Parliaments and the Logic of Arguing in the EU*

The 2004 Constitutional Treaty features an ‘early warning system’ (EWS) in which national parliaments will scrutinize European legislative proposals to assess whether they comply with the principle of subsidiarity. In constructivist terms, this procedure effectively sets up the Commission and the national parliaments as interlocutors in an argument over when and how the EU should legislate. At a minimum, this system – which should be expanded to include proportionality – will alleviate the ‘democratic deficit’ by enhancing the parliamentary scrutiny of EU legislation. If it works well, it will improve the subsidiarity compliance of EU legislation and produce a clearer substantive definition of the principle.