The Lisbon Treaty has led to an expansion of the rights of parliaments in scrutinizing EU decision making, including—for the first time—also regional parliaments. Yet, theoretically informed empirical work on how regional legislatures adapt to the increasing relevance of the EU for subnational jurisdictions remains scarce. Drawing on data from an original survey of 251 MPs, conducted in seven German Länder in 2011, we explore regional MPs' involvement in EU affairs. We find strong variation among MPs' level of EU involvement. Exploring different sets of explanations, we show that individual-level factors—the perceived salience of the EU and MPs' perceived influence in EU matters—hold the highest explanatory power.
