The constitution of the Fifth Republic introduces a new concept of the role of a President of the Republic, whose authority is strengthened as compared to the limitation imposed upon that office by the provisions of Constitutions of the Third and Fourth Republic. Article 5 of the Constitution of 1958 defines, in a general way, the function of the president, making him as a head of state, the guardian of the constitution and guarantor of national independence, integrity of state territory and respect for treaties as well as an arbiter responsible for proper functioning of public authorities and existence of the state. The notion of arbitration constitutes an essential element of this article, which causes some interpretative problems due to its ambiguity. In fact, the wording used in this provision seems to be reasonable, as it synthetizes the function of the President depending on political circumstances: it can take the form of a pro-active and resolute arbitration (beyond the period of cohabitation), and some other time, can be carried out with reserve, in a more symbolic way (in the period of cohabitation) Irrespective of external circumstances, the functions of President of the Fifth Republic, empowered by the democratic legitimacy derived from universal and direct elections, are not limited to formal and representative dimensions. Since 1958, the President of the Republic is a driving force behind the operation of the executive power. Problems with relations between the President of the Republic and the Prime Minister on the ground on the basic law result from the overlap of two provisions: the above-mentioned Article 5 and Article 20. The latter confers on the government the right to 'conduct' and 'outline' the national policy. These controversies, even if no longer topical, ensue from an erroneous (in the author's opinion) assumption that one of those two provisions must be applied in its entirety. Such a choice is of an arbitrary nature. However, we should rather try to find a way to apply at the same time both the provisions without distorting the will of the authors of the Constitution. The two provisions can be applied simultaneously, but with different and variable intensity depending on political circumstances. When the President performs his role of a resolute arbiter (beyond the period of cohabitation), Article 20 is applied selectively, and the government limits itself to pursue the policy determined, to a considerable extent, by the President of the Republic. But when the President's role of arbiter is weaker, Article 20 operates with no limits, and the government can pursue a policy of its own.