Omparative Constitutional Law: Subsidiarity Principle

This law research paper will need to be well argumented, well researched and also very logical.
It is about the subsidiarity principle and its effectiveness or failure, depending to which conclusion you will arrive. It will be necessary to compare at least three countries from which one can be the US and one also could be the European Union. If you believe the subsidiarity principle to be effective, you need to prove the success with examples, so not only show were subsidiarity is to be found in the constitutions but also how it has been used. The sources have to be reliable and scholarly and not from wikipedia. If you use internet sources it will also be necessary to explain why the source is reliable.