Carl Schmitt's name is irrevocably linked to the label of decisionism, the theory according to which the ultimate foundation of right is the sovereign's political decision. This paper aims to show how the juridical decisionism of Schmitt has changed without becoming contraditory as it assimilated in the thirties the '"juridical institutionalism" of authors like Hauriou and Santi Romano. Following those years Schmitt worked out the meaning of a decisionism based on the "concrete order thought", namely, the institutionalist decisionism.