Introduction

The Introduction presents the rationale, the research questions and the hypotheses of the Special Issue. While the European Parliament (EP) has unquestionably been one of the winners of the Lisbon Treaty, its empowerment has taken place while several crises – from the financial crisis to Brexit – hit the EU. Against this backdrop, it sets the scene for the questions that will guide the various articles of the Special Issue: to what extent has the EP effectively used the new powers conferred to it by the Lisbon Treaty? What conditions have favoured or limited its capacity to shape policies? In testing times for integration, the EP often struggles to translate its institutional powers into policy influence. The articles in this collection show that this is more likely to happen when issues are close to the sovereignty of the member states, and when decisions generate well-identifiable costs at the national level.