Carl Schmitt, Political Theology: Preface to the Second Edition

In this preface (written ten years after the original publication of the book), Schmitt amends his typology of legal theories. He had originally categorized legal theories as either normativist or decisionist. He now adds institutionalism as a third type. I am curious about how well these translate into schools of Anglo-American legal theory. My guess is that normativism, due to its sense of closure, is akin to positivism and decisionism is closest to realism. I am at a loss to make sense of his brief critique of each of these legal theories, but he thinks that, in isolation, all of them are lacking.