One key indicator of profound change in a Westphalian state order might be the extent to which cleavages are cross-cutting national borders. The kind of conflict structure found at the European level is supposed to be highly dependent upon the institutional architecture at that same level. Arguably, a peculiar thing about the EU’s institutionalset-up is that it might be able to generate a multi-dimensional cleavage pattern at the European level. In that case, power becomes significantly redistributed, and serious conflicts along a single axis are less likely to develop. If EU institutions really are that important, then we have to address more systematically the processes through whichthey themselves come about and change. Prevalent rational choice explanations, including liberal intergovernmentalism, have their shortcomings when profound institutional change is to be accounted for, and, particularly so, if such change is intended.