For det første skal alle de medlemsstater, som ønsker at deltage i dette samarbejde, til enhver tid kunne deltage i det. For det andet skal de kriterier og regler, der kommer til at gælde for dette samarbejde, ikke besluttes af de medlemsstater, som starter samarbejdet, men vedtages af Det Europæiske Råd.
Firstly, that this cooperation is open at all times to all Member States of the European Union which wish to participate in it; secondly, that the criteria and rules according to which this cooperation is set in motion do not stem from a decision made by the States which initially establish this cooperation, but are approved by the European Council.