In the last decades there has been new «cases» for the theory of the just war. This theory is more and more invoked to justify military interventions, thus becoming increasingly comprehensive. This led one of the most known and discussed interpreters, Michael Walzer, to an apparent radicalization of his former positions, tending to define the limits more than the possibilities of military interventions. This extension shows the vitality of the theory, but on the other side reveals more patently its aporias, and more, it risk to give the way to a sort of «short-circuit» both in regard of other Walzer’s theories (such as the pluralistic approach, the emancipative possibilities of «inner criticism», the central role of politic in the human vicissitudes, the crucial relevance of social justice), and in regard of the «secular» form of justification and the legimization of military conflicts which is brought about by the same idea of the «just» war.