Separated powers were and remain an inventive device to achieve important democratic values in presidential systems. These values include thwarting the rise of government tyranny, preventing the arbitrary exercise of government power, and promoting the efficient administration of the state. But these core values of democracy are likewise achievable, albeit in varying degrees, in parliamentary systems. Whether those parliamentary systems separate powers in an unconventional fashion as in British parliamentarism or in a juricentric fashion in typical of constrained parliamentary systems, or between two independent executives like semipresidential systems, those three democratic values may indeed be achievable, though perhaps not in all circumstances. This is a profound point because it suggests that the democratic and structural advantages of separated powers are not inherent exclusively in presidential systems but may also be attainable in parliamentary systems. It is even more important because it leads to new possibilities for constitutional design.
Constitutional theory has long regarded the separation of powers as unique to presidential systems and incompatible with parliamentary ones. In this Article, I suggest that the core values of the separation of powers are achievable in both presidential and parliamentary systems, contrary to the conventional wisdom which insists that the separation of powers is the exclusive province of presidentialism. This conclusion – that parliamentary and presidential systems are comparably receptive to the practical and philosophical strictures of the separation of powers – unlocks interesting possibilities for rethinking constitutional structure anew.