The classical economists have mostly focused their attention on the functioning of the market and not on the role of the state. The analyses of various democracies are based on the assumption that the State decisions once made are applied as intended by the authorities who are responsible for their practical implementation. The economics of regulation is situated at the intersection of the public economics and industrial economics, it explores different forms of government intervention in industrial activities to simulate either to control or even to reprove them. Public intervention can take different forms: in Europe the most common practice is the nationalization, it is the public monopoly of law. In the United States operation of this natural monopoly is assured through economic regulation, that is to say all means by which Governments directly influence the activity of companies while maintaining the framework of the private property. It is very important to distinguish between the economic regulation of an activity that focuses on the price and the determination of the structure of offer, and the social regulation concerning the conditions for the exercise in the activity and the physical characteristics of the products or services (protection of workers in their working conditions (health, security), rules of environmental protection or standardization of products (quality).