Following the focus of the 2009 EUSA conference EU-CONSENT panel on ‘Theorising “EU
Deepening and Widening”: A Return to Grand Theory?’ this paper presents main aspects and
outcomes of the theoretical work of the Network of Excellence EU-CONSENT over the past
four years. The paper presents a set of multi-disciplinary ideas and assumptions about
interrelated causes and effects of EU widening and deepening. It discusses and reflects on
how to merge these assumptions and the approaches of different academic disciplines into a
more integrated structure to further guide and conceptualise research. It elaborates on
assumptions developed as common points of reference and proposes ideas for a theoretical
link between EU deepening and widening. By doing so, the paper seeks to contribute to
bridging a gap in European integration theory: Despite the seeming interconnectedness of
current developments in EU deepening and widening, the relevant knowledge to explain and
evaluate this claim from an academic point of view still remains a desideratum. In how far
such a link can be established is subject to discussion of the present paper
