The independence of the European Central Bank from european governments and institutions is almost absolute. It depends only partially on the achievements of the monetary theory. Two factors have to be considered, a cultural one and a political one. First, the diffusion, in the last two decades, among social scientists and public opinion of beliefs about the seriousness of politics' failures in comparison with market's failures. Secondly, the reciprocal distrust between the european governments which subscribed the Maastricht Treaty, that is, the independence of the ECB is the assurance which the european nations with the best inflation performance obtained against the opportunistic behaviour of their partners. The limits of the Maastricht Treaty which derive from these causes may be overcome by an "european constitution" containing a more balanced relation between the ECB and european political institutions.