Collingwood emphasizes the importance to work with the historical knowledge, despite already known, the historian does not limit itself to reconstitute the passed thought, makes its reconstitution in the context of its knowledge. In this manner, when reconstituting it, it criticizes it form a proper judgment on its value, corrects any errors that obtain to discern in it. This critical one of the thought, whose history it traces, is not by no means secondary in relation to the delineation of its history. It is an indispensable condition of the proper historical knowledge. Therefore, the historical, known, but not established knowledge, needs experiences of thoughts and passed reflections, without which the historical fact is only register. Fitting to who it studies and it analyzes these facts, to make its reflections and to establish its agreement, that is, ' ' prprio' forms a judgment; ' , despite from secondary sources, what it does not invalidate the reconstitution and the critical one.
A typical problem, in regards to the use of the bibliographical and thematic material: certain times, that if it goes to deal with certain conjunctures, have its dependent interpretation of suggestions or projects supplied for determined authors. But on the other hand, the workmanships of these authors are in this or that chronological or ideological position. Therefore, with the vision of the gift and established experiences already, but without definitive versions on passed facts, and ideological condicionantes, since any opinion can be contested, from new constataes and new facts that if present as it clarifies Adam Schaf: ' ' The truth reached in the historical knowledge is a truth relativa' ' , that we will look for to understand and to analyze the considered historical events. It is, therefore, our proposal of work, to present the violence institutionalized in its diverse forms, mainly policeman, that is, duly covered for emergency laws edited before and validity of the New State, when Getlio Vargas governed Brazil of ditatorial form.