Demographic explosion and industrialization forced sovereignty to yield to biopower.

Evidence

One might say this: It is as though power, which used to have sovereignty as its modality or organizing schema, found itself unable to govern the economic and political body of a society that was undergoing both a demographic explosion and industrialization. So much so that far too many things were escaping the old mechanism of the power of sovereignty, both at the top and at the bottom, both at the level of detail and at the mass level. A first adjustment was made to take care of the details. Discipline had meant adjusting power mechanisms to the individual body by using surveillance and training. — Michel Foucault, Society Must Be Defended, 7132