This chapter is devoted to mid-century systems theory, which, I argue, is where the behavioralist solution to the problem of social order found its paradigmatic – and also its theoretically most problematic – expression. Specifically, the chapter considers David Easton’s theory of the political system as the most explicit effort to thematize and theorize the problem of social order that the discipline has seen. The effort ended, I show, in an undecidable vacillation between political authority and societal consent to authority as the ultimate source of social order.