This article uses post-referendum Flash-Eurobarometer surveys to analyse empirically voter attitudes towards the EU Constitution in four member states. The theoretical model used incorporates first and second order variables for voting to ascertain whether the outcome of the vote was a reflection of either first or second order voting behaviour. It is hypothesised that the cleavage politics over integration in the European arena had a major impact on the four votes, as captured by three first order variables: ‘Europhile’ and ‘Constitution-phile’ attitudes and ‘Egocentric Europeanness’, respectively. The quantitative analyses – controlling for a number of dimensions – strongly supports the hypothesis when compared with a model using solely second order party identification variables. These findings establish that how voters understood the EU polity, in particular whether membership is beneficial to one's own country, was a crucial factor in all the referendums. Implications for future research include the need to discover the cues or proxies influencing first order voting within domestic politics.