Just like the preceding one, this option would consist in permitting some EU Member States, those that are willing and able, to cooperate together at a faster pace than the other Member States. One of the differences between the two options is that, in the second one, the group of participating states would be established legally, through the conclusion of an international agreement. This ‘additional treaty’ would specify the rules and procedures under which the participating states would decide to cooperate together, while continuing to fully respect the EU treaties.

At first sight, the group could be expected to be composed on the basis of the list of the Member States that have already demonstrated their willingness to go ahead by participating in the euro area. Whether that would be not only a necessary, but also a sufficient, condition is a political issue which would have to be considered by the Member States concerned. Another major closer cooperation is, of course, the Schengen area, and participation in the Schengen area could also be considered as a political condition for acceding to the group by the states that would launch the project. Common views as regards defence issues could also be taken into account.