Marx, on several occasions, registered his plan to devote a volume of Capital to the state. At the time of his death, however, this volume remained unwritten. Subsequently, students of Marx have proven hesitant to theorize the distinct organizational schema of modern state power, and the way it mediates and enriches those tendencies identified by Marx in Capital’s first three volumes. Instead, the capitalist state is often distinguished by pointing to its disaggregation from the economic structure of society. The following paper will return to Marx’s proposed volume on the state, using a number of recently published scholarly tracts to consider its potential analytical orientation. Particular attention will be paid to Foucault’s late work on governmentality which, it will be argued, offers a useful starting point for conceptualizing modern state power, and the historically distinct ways it forms part of capitalism’s interior.