Starting from the century-long tradition of the Independent Commissions, the author describes the political and institutional features of the American system. Political factors rather than legal indices measure the real significance of the concept of independence in the North American experience. In the absence of the idea of organizational independence of the commissions from the political organs, the individual independent commissions have managed to develop a functional independence by virtue of their dependence on both Congress and the president. They are the only bodies able to combine technical-scientific expertise, which is particularly valued by a liberal view of economic regulations, with political orientations which are not the expression of one single party. It is the endeavour to eliminate the political bias deriving from control by one political party, more than independence from the executive, which connotes - according to the author - the North American system of independent agencies.