Summary of Results
Overall, the findings are largely in line with the theoretical expectations and with the descriptive evidence of the previous section. Whether parliamentarians support reform proposals to strengthen national parliaments' rights and capacities to participate directly in EU policy-making depends on their constitutional preferences. Intergovernmentalists, compared to federalist representatives, tend to oppose inter-parliamentary cooperation and a joint national committee with members of the EP. The impact of constitutional preferences depends, however, on the characteristics of the proposed reforms. If suggested institutional changes are compatible with a parliamentary focus on domestic oversight, as in the case of the proposal to reinforce parliamentary ties with the European Commission, intergovernmentalists are not necessarily opposed. At the very least, their opposition becomes less consistent across deputies and countries. Having said this, the impact of constitutional preferences is trumped by that of existing domestic and EU-related institutions. Where the strength of existing parliamentary rights and capacities indicates that national policy-makers see the focus of the parliaments' role in the interaction with the national government, parliamentarians oppose a direct role in EU affairs. This effect is especially pronounced in the case of existing EU-related oversight institutions. It is likely that past domestic adaptation efforts of national parliaments have such a strong effect because they themselves result from domestic institutions and constitutional preferences and, thus, are best interpreted as picking up indirect effects of these more fundamental explanatory factors. Moreover, instrumental considerations presumably add impact to EU-related oversight institutions. In parliaments that already have rights and capacities in EU affairs, the added value of a direct European role, and the investments of time that might be related to such a role, do not appear worthwhile to parliamentarians.
The individual-level preferences of parliamentarians matter because, as Chapter 3 argued, party leaders seek to build inclusive parliamentary positions on reforms of national parliamentary rights and capacities in EU affairs. Otherwise, they risk that the considerable diversity of constitutional preferences that exists within parties turns into publicly visible conflict, which might damage the party's electoral prospects and the reputation of the leadership. However, whereas domestic reforms of national parliamentary rights can be settled among national politicians, some possibilities to strengthen national parliaments' direct role in EU affairs require agreement between countries. Take, for instance, a proposal to reinforce inter-parliamentary cooperation. All parliaments, and probably also all national governments, would have to agree to such a reform at least to the extent that it should be embedded in the EU's formal constitutional framework. Scholars have already shown that disagreement between parliaments and countries has prevented ambitious reforms of parliaments' direct European role (Rittberger 2005: 177-96; see also Raunio 2009: 322-5; Bengtson 2007). The following section provides an illustration of how parliaments with divergent constitutional preferences interact and how this interaction prevents agreements on ambitious reforms.