Follow-ups to this article: here, here & here. With the Lisbon Treaty entering into force next month, one particular issue that has been part of legal and political discussions for years will become pertinent: The EU's accession to the European Convention on Human Rights (ECHR).
All EU member states have ratified the Convention and most have also signed and ratified the additional protocols to the convention (including the protection of property rights and free elections [Protocol 1] or the prohibition of the death penalty under all circumstances).
The rights guaranteed by the ECHR are supervised by the European Court of Human Rights (ECtHR) in Strasbourg. Since through its member states the legal traditions of the ECHR are also informally part of the EU's legal traditions, the European Court of Justice (the EU's court) is already taking into account rulings of the European Court of Human Rights, but so far there is no legal obligation for the Union to follow the Human Rights Convention's provisions.
However, now that the Lisbon Treaty will enter into force, the EU is getting legal personality and is thus able to join international agreements outside the scope of the former European Community, including the ECHR.
And, for those who did not have time yet to read the Lisbon Treaty, the document explicitly foresees that the EU will join the European Convention on Human Rights (which might mean that the EU institutions will be subject to rulings of the non-EU ECtHR). It deals with this matter in Article 6 of the Treaty on European Union (TEU) and in the Article 218 of the Treaty on the Functioning of the European Union (TFEU) as well as in the Protocol 8 and the Declaration 2 to the Lisbon Treaty.
In short, these provisions foresee that the EU shall in fact join the ECHR, but only after the EU and the member states have agreed on how the EU's legal and practical relations with the different control bodies of the convention will be and after it is clear how one will differentiate between law suits against the EU and those that would go against a member state (which could become difficult when it comes to the execution of EU law in the member states).
In the end, the Council needs to decide unanimously on the accession to the ECHR, and all member states will have to agree individually according to their constitutional provisions.
Although this is now clearly prescribed by the Lisbon Treaty, this is still going to be a very difficult legal and political process, not least seeing the debates around the Charta on Fundamental Rights and Freedoms in some member states or the latest "outrage" in Italy against the Crucifix judgement by the ECtHR.
And so even though the Council of Europe - the international organisation built around the European Convention on Human Rights - is already starting to pressure on the EU start its accession procedures, this could take some time until the EU has ruled out all complex legal and practical problems related to this accession.
Therefore, I expect the process to be quite controversial already between the EU member states and EU institutions (including its legal services), but also between the EU and the Council of Europe (including the other 20 signatory states to the European Convention on Human Rights) - and the result will probably be an unprecedented case of legal interdependencies between two different supranational regimes.