1. Parliaments of constitutional regions, being endowed with legislative power, must be included in any future scheme of collaboration between the European parliament and Parliaments of the Member States. The totality of the Parliaments of the Union, each working within its particular sphere of competence, constitutes a set of complementary mechanisms enabling citizens to exercise effective control over the exercise of public power at all levels.
2. However, when it comes to a body such as a "Convention" deliberating in the run-up to an Intergovernmental Conference such as that of 2004, it is difficult for even constitutional regions to make out a case for some special right of participation. The Convention seeks to represent the States' parliaments and their governments, the European Parliament, and the European Commission, and to give involved observer status to candidate countries. There is a limit to how large a viable Convention can be, and there are many parliaments with legislative power at the regional level throughout the Union.
3. It has already been noted, however, that the larger Member States have proportionally smaller representation in the Parliament than smaller ones, and this creates distortions as between constitutional regions (especially internal nations) within large states and independent member states that are similar in size to them. In this context, it could be argued that member states having a population larger than some given threshold should be entitled to two government representatives, provided that the second representative was a nominee of regional rather than of central government. Alternatively, the parliamentary representation could be structured with a view to playing this role, and would probably be the case, in e.g. Germany or Austria. But this would not obviously fit the current structure of the UK Parliament, and it is not on the face of it likely that special arrangements will be made.
4. This poses sharply the issue whether regional status is adequate in the case of Scotland or similarly situated countries. It is at the heart of Scottish constitutional debate whether a nation that currently has the status of a constitutional region within a union state gains adequate advantages within the European Union from its present situation. In particular, are such (alleged) advantages sufficient to outweigh the disadvantages such a nation has in comparison with similarly sized nations that are Member States of the Union? National parties in several internal nations, among them the SNP, have it as their explicit political goal to achieve national independence within the European framework. In the nature of the case, the internal nations are entities that substantially satisfy already the `Copenhagen criteria' that apply to countries seeking entry to the EU from the outside. If they were external states applying for admission as candidate countries, their path would be a clear one. It would be desirable for all parties to constitutional debate in Scotland and similarly situated nations to work towards establishment of clear doctrines concerning pathways to `internal enlargement'.