The purpose of this chapter has been to examine whether the assumptions and mechanisms underlying this study's argument play out as expected in the parliamentary arena. Do parties adopt positions on parliamentary reform in accordance with their constitutional preferences? Do they put forward corresponding arguments? Do they come to the consensual agreements that would justify the fact that the theory refers to 'parliamentary parties' collectively? The chapter has examined Dutch reform debates from the mid-1980s to the ratification of the Lisbon Treaty. The Netherlands are interesting not only because of several observable reforms, but also because of their sector-specific 'approval rights' in justice and home affairs, introduced in the early 1990s and nearly abolished with the entry into force of the Lisbon Treaty. Moreover, the constitutional preferences of the Dutch parliamentary parties have undergone a subtle yet relevant shift towards intergovernmentalism since the late 1990s. An explanation of EU-related parliamentary rights should be able to capture the arguments and mechanisms underlying the Dutch parliament's reforms, and also reflect the temporal shifts in the parties' constitutional preferences.
There is considerable support for the theoretical argument. Parties position themselves towards parliamentary reform in expected ways. Federally oriented and intergovernmental parties alike consider stronger parliamentary rights necessary in order to remedy perceived democratic shortcomings of the European integration process. However, whereas the former set of parties welcomes the empowerment of the EP, and is willing to limit their domestic reform demands in response, intergovernmentalists see no significant benefit in the EP's authority and demand strong national rights. As the example of the parliament's introduction and abolition of approval rights shows, moreover, even federally oriented parties will demand strong EU-related national parliamentary competences if EU authority does not go together with co-decision powers of the EP. Furthermore, the gradual shift of the Dutch parties away from strongly federal constitutional preferences manifests itself in a more cautious view of the ability of the EP to secure the Union's democratic legitimacy, and in demands for the introduction of a scrutiny reserve procedure. In this respect, the chapter suggests that intergovernmental inclinations among parliamentary parties do not only affect the likelihood but also the extent of reform. In Chapter 4, we saw this effect but it was not statistically significant.
Finally, notwithstanding discrepancies in parties' constitutional preferences, especially during the Lisbon ratification, the eventual reform outcomes have always been approved consensually by 'parliamentary parties' acting collectively, and in spite of explicit objections of 'the government'. For example, the introduction of the scrutiny reserve and the near-abolition of the approval rights after the Lisbon Treaty is an outcome in which governing and opposition parties both had to make concessions.