More Schmitt

The methodological sections of Political Theology seem to look forward to Althusser and the concept of structural causality—as does indeed the notion that the modern state is based on displaced theological concepts. Schmitt is concerned to show that democracy is a political concept which has the same structure as the metaphysics of immanence, which in turn is an expression a general de-transcendentalizing of what is in effect the dominant ideology. These relations are not causal in a base-superstructure way, they are serialised structural effects.
The more interesting question then: is what is precisely at stake in this echo from Schmitt to structural marxism?