1. The Union shall develop a policy with a view to:
(a) ensuring the absence of any controls on persons, whatever their nationality, when crossing internal borders;
(b) carrying out checks on persons and efficient monitoring of the crossing of external borders;
(c) the gradual introduction of an integrated management system for external borders.
2. For the purposes of paragraph 1, the European Parliament and the Council, acting in accordance with the ordinary legislative procedure, shall adopt measures concerning:
(a) the common policy on visas and other short-stay residence permits;
(b) the checks to which persons crossing external borders are subject;
(c) the conditions under which nationals of third countries shall have the freedom to travel within the Union for a short period;
(d) any measure necessary for the gradual establishment of an integrated management system for external borders;
(e) the absence of any controls on persons, whatever their nationality, when crossing internal borders.
3. If action by the Union should prove necessary to facilitate the exercise of the right referred to in Article 20(2)(a), and if the Treaties have not provided the necessary powers, the Council, acting in accordance with a special legislative procedure, may adopt provisions concerning passports, identity cards, residence permits or any other such document. The Council shall act unanimously after consulting the European Parliament.
4. This Article shall not affect the competence of the Member States concerning the geographical demarcation of their borders, in accordance with international law.