The Lisbon Treaty has renamed the European Security Defence Policy (ESDP) by Common Security and Defence Policy (CSDP). The CSDP will “provide the Union with an operational capacity drawing on civilian and military assets” for use “on missions outside the Union for peace-keeping, conflict prevention and strengthening international security.” The necessary military and civilian capabilities for these tasks will be provided by the Member States, whereas decisions on the implementation of the CSDP, such as the launch of operations, will be adopted by the Council. The new Article 43 TEU defines the operational remit of the Union's  CSDP. Under this Article the Union may use civilian and military in joint disarmament operations, humanitarian and rescue tasks, military advice and assistance tasks, conflict prevention and peacekeeping, and tasks of combat forces undertaken for crisis management, including peace making and post conflict stabilisation. This provision widens the Union's potential in terms of the fight against terrorism, conflict prevention missions, post-conflict stabilisation missions. Under the new provisions introduced by the Lisbon Treaty, Member States are required to provide civilian and military capabilities for the Union for the implementation of the common security and defence policy. The Lisbon Treaty also introduced the Permanent Structured Co-operation, a framework by which a group of Member States can decide to build closer relations and co-operation. It is for the Member States who want to be committed to take part in main European military equipment programmes and to provide combat units which are available for immediate action to the Union.

The Lisbon Treaty has marked the start of a new phase of defence integration for the EU. Whilst signing the Lisbon Treaty, all Member States have become committed to the goal of a common defence. This amounts a major transfer of power from the Member States to the Union.

Brussels is already discussing the implementation of the Lisbon Treaty in terms of a Common Security and Defence policy. The EU Belgian Presidency is particularly interested in discussing the options for possible implementation of the Permanent Structured Cooperation in order to enhance the Union defence capabilities. At his first “State of the Union” address before the European Parliament, the President of the European Commission, Jose Manuel Barroso said that Brussels is “making progress on a common foreign policy”, moreover he said “we will not have the weight we need in the world without a common defence policy. I believe now is the moment to address this challenge.”

On 24 September, at an informal meeting, the EU Member States’ defence ministers discussed the implementation of the instruments as well as the new possibilities given by the Lisbon Treaty in the field of the Common Security and Defence Policy. They agreed to enhance defence cooperation by sharing and pooling military capabilities in order to reduce costs at a time when member states’ defence budgets are being cut. The European Defence Agency has been requested to produce a report stressing in which areas/projects such further cooperation can be achieved. According to Euractiv, Pieter De Crem, Belgian Defence Minister, noted that an agreement has been recently signed by Netherlands, Belgium, France and Germany intend to “pool 200 transport aircraft under a single command”, he said "This is the kind of cooperation we will be developing more.

The High Representative of the Union for Foreign Affairs and Security, Catherine Ashton, said that the Union needs “more co-operation in order to continue to deliver in a very difficult budgetary situation.” Ms Ashton has identify a double challenge “on the one hand we are faced with enormous pressure on public finances and defence budgets” but “On the other hand, there is a strong demand for the EU to be more active…” According to the High Representative “we need to turn the crisis into an opportunity.” Unsurprisingly, Brussels is once again using the financial crisis as an excuse to move forward with further integration. Ms Ashton wants, therefore, to use all the “possibilities offered by the Lisbon Treaty.” She said to the EU defence ministers “we should focus our spending on our agreed priorities” and “explore ways of pooling and sharing.”

The Member States have not debated yet a possible implementation of the so called Permanent Structured Cooperation. However, taking into account the current economic situation and the substantial cuts on the member states defence budgets, such idea is gathering support among several  member states. As abovementioned, Brussels is seeing the present economic and budgetary situation as an opportunity for further develop civil-military cooperation between member states. Permanent Structured Cooperation is one of the priorities in the Belgium EU Presidency work program with regard to security and defence. Belgium, Hungary and Poland, next EU Presidencies, want to move forward on the concept of permanent structured cooperation in defence. In a joint statement they said that "the instrument of Permanent Structured Cooperation (PESCO) can bring about a new dynamic among Member States that want to cooperate militarily within the framework of the Union in order to improve the European defense capabilities with a view to carrying out the most demanding missions." Moreover, they stressed that "In the current economic and budgetary context ever fewer nations will still be capable to develop such capabilities individually," consequently, according to these member states "better cooperation should also eliminate the current duplications and identified shortfalls with regard to defense capabilities." However by having in place a Permanent Structured Cooperation Brussels will move forward towards military and defence integration. It is a step towards a Single European Army. In fact, following the entry into force of the Lisbon Treaty several Member States, namely Germany, France and Italy have called for a European Army.

Last July, the Belgian EU Presidency has held a Seminar on Permanent Structured Cooperation. According to a press release Pieter De Crem pointed out that the Permanent Structured Cooperation allows giving “a political incentive for a gradual shift from purely national defence planning to a more “Europeanized” one.” Moreover, he stressed that this is “a project which needs political will as a basic condition for success.” Under the new Article 42 (6) “Those Member States whose military capabilities fulfil higher criteria and which have made more binding commitments to one another in this area with a view to the most demanding missions shall establish permanent structured cooperation within the Union framework.” This Article establishes the arrangements how Member States can engage in permanent structured cooperation and the Protocol on Permanent Structured Cooperation sets out the criteria and capability commitments for doing it.

The Member States who wish to participate in the permanent structured cooperation shall notify the Council and the High Representative of the Union for Foreign Affairs and Security Policy of their intention. Such structure looks like euro zone as not all the Members States will be able to participate in the defence group because not all fulfil the requirements and others will not participate because they do not want to. According to the abovementioned Protocol the participating Member States have to agree in intensively proceed to develop their defence capacities through the development of their “national contributions and participation, where appropriate, in multinational forces, in the main European equipment programmes,” and in the activity of the European Defence Agency “in the field of defence capabilities development, research, acquisition and armaments” and they have to have “the capacity to supply by 2010 at the latest, either at national level or as a component of multinational force groups,” combat units and supporting elements such as transport and logistics, capable of carrying out the tasks such as disarmament operations, humanitarian and rescue, conflict prevention and peacekeeping “within a period of 5 to 30 days, in particular in response to requests from the United Nations Organisation, and which can be sustained for an initial period of 30 days and be extended up to at least 120 days.” Furthermore, the Protocol also puts forward measures that the participating Member States will have to carry out such as harmonising the identification of their military needs, pooling of assets, cooperation in the areas of training and logistics, identifying common objectives regarding the commitment of forces. It is stressed the possibility of review of national decision making procedures in what concerns the deployment of forces.

According to the Belgian-Hungarian-Polish joint statement "It is in the EU's best interest to involve as many interested member states as possible in this institutionalised defence cooperation," consequently "PESCO should not be limited to a core group of a small number of countries […] A two-speed European defence needs to be avoided."

The Conservative party has been strongly against to the Lisbon Treaty’s defence provisions, including permanent structured co-operation. Before the informal meeting of EU defence ministers, Geoffrey Van Orden MEP has called for an EU army to be halt. He stressed that the Conservative party has “consistently sought to lay emphasis on the primacy of Nato, on our relations with the US and other key allies such as Norway and Turkey, and on the need to avoid waste and duplication at a time when defence resources are scarce." Recognising that will be a “difficult task” for the UK defence minister “to encourage his EU colleagues to move in this direction”, he said "... I am confident that we will put down a strong marker that duplication of Nato and wasteful EU vanity projects will not be accepted."

It is important to recall that, after consulting the High Representative, the Council will decide by QMV, to set up the permanent structured cooperation and determine the list of participants Member States. As it will decide by QMV Britain will not be able to veto such decision. Therefore, the permanent structured cooperation might be established against the will of some Member States. The participating Members will use the CFSDP for their own purposes. Moreover, once the permanent structured cooperation is established only participating Member States are allowed to adopt decisions relating to the development of structured cooperation as well as the future participating Member States.