Which policies should the European Union (EU) regulate? Which issues should national governments regulate? This is a crucial issue within the EU. Citizens in EU member states have had little influence on decisions allocating political decision-making powers between the supranational and the national/regional levels. Given this situation, it is important to study the supranationalism of people in different European countries. The issues addressed here are the following: - How can one determine the supranationalism of European citizens? - Is the homogeneity of these opinions such that one scale can be used for the whole of Europe? Data used are obtained from the first round of the European Social Survey. The paper reports on an effort to develop a cumulative (Mokken) scale of supranationalism. The paper concludes that one unique scale does not exist that is applicable to all European countries; however, different cumulative scales can be constructed for four clusters of countries. Finally, cross cultural comparisons are carried out testing different hypotheses relating the level of supranationalism with political trust, age, education and establishment in the area.