But, what we mean by public necessity?. At this point we are the criterion that the so-called public necessity is the widespread lack of a population with respect to a particular State public service. This is common deficiency that injures a particular population which requires the State to take as an exceptional measure the expropriation. At our discretion, the activity considered as public service has experienced, to the length of its history, conceptual crisis expressing, in short, a serious questioning of the effectiveness of this technique of administrative intervention. The proper valuation of the public service requires a contextual political, social, economic, and ideological. At this point it should be noted, that in the case of Peru, there is a definition, nor a single legal framework applicable to public service. In fact, in our opinion, public service arises as a technique of administrative intervention from the exclusive use of the public domain, as would bring DUGUIT public service is any activity whose fulfilment must be regulated, secured and controlled by the rulers to be essential to the implementation and to the development of social interdependence and of such a nature that can not be secured completely rather than by the intervention of the force ruling; This state service is which materialized because of a public need.
However, to date are discussed endpoints that would encompass the concept of public necessity; We have an example of this in the judgment the Court Supreme of the U.S. in the KeloV affair. City of New London in 2005. The Supreme Court of the United States failed one of the most controversial cases in recent times by the more meagre majority (5-4). The municipal Council of New London (Connecticut) approved a regulation by which certain private properties would be expropriated in order to promote the development of an urban area and complete facilities that the Pfizer pharmaceutical planned to build.