The "Commune" is the basic collectivity. Art. 16 - The elected assembly represents the basis of decentralization and a place of the citizens’ participation in the management of public affairs. Art. 17 - Public property belongs to the national collectivity. It includes the underground, the mines and quarries, the natural ressources of energy, the mineral, natural and living ressources in the various national maritime areas, waters and forests. It also includes rail, maritime and air transport, the mail and telecommunications as well as other properties defined by the law. Art. 18 - The national properties are defined by the law. They include public and private properties of the State, the "Wilaya" and the "Commune". The management of the national properties is carried out in accordance with the law. Art. 19 - The organization of external trade is the domain of the State only. The law defines the conditions and control of external trade. Art. 20 - Expropriation can be carried out only within the framework of the law. It gives right to a prior, just and fair compensation. Art. 21 - The functions in the State institutions should neither be a source of wealth nor a means of being for the service of private interests. Art. 22 - Power abuse is repressed by the law. Art. 23 - The administration’s impartiality is guaranteed by the law. Art. 24 - The State is responsible for the security of persons and properties. It ensures the protection of every citizen abroad. Art. 25 - The enhancement and the development of the defense capacity of the Nation are organised within the National People’s Army. The permanent task of the National People’s Army is to safeguard the national independence and to defend the national sovereignty. It ensures the defence of the country’s unity and the territorial integrity as well as the protection of its terrestrial and air space, and the various areas of its maritime space. Art. 26 - Algeria does not resort to war in order to undermine the legitimate sovereignty and the freedom of other peoples. It puts forth its efforts to settle international disputes through peaceful means.