[USFRIENDINVICTORIA]

“Subsidiarity is very important.”

Subsidiarity seems to be a principle of federation, more honoured in the breach than the observation. (IOW, federal governments love to trample on state rights.)

[Olog-hai]

The way the European Union regards “subsidiarity” is from the viewpoint that the national governments are subsidiaries of the federal one.

Under the principle of subsidiarity, in areas which do not fall within its exclusive competence, the Union shall act only if and in so far as the objectives of the proposed action cannot be sufficiently achieved by the Member States, either at central level or at regional and local level, but can rather, by reason of the scale or effects of the proposed action, be better achieved at Union level.

— Treaty of Lisbon, Article 5, Paragraph 2

As far as “exclusive competency” (i.e. only the Brussels government would hold these powers and no member state can exercise them), this is what they consist of:

1. The Union shall have exclusive competence in the following areas:
   
   
   1. customs union;
   2. the establishing of the competition rules necessary for the functioning of the internal market;
   3. monetary policy for the Member States whose currency is the euro;
   4. the conservation of marine biological resources under the common fisheries policy;
   5. common commercial policy.
   
   
2. The Union shall also have exclusive competence for the conclusion of an international agreement when its conclusion is provided for in a legislative act of the Union or is necessary to enable the Union to exercise its internal competence, or in so far as its conclusion may affect common rules or alter their scope.

— Treaty of Lisbon, Article 3, Treaty of European Union section

IOW, all the powers that make a sovereign nation sovereign are conferred upon the EU’s federal government exclusively.