Keywords: Social Part; Political Party; Parteienstaat; Representative Democracy.
The emergence of modern political party is internal to the epochal break with the plu¬ralist conception of the body politic typical of the Modern age. Even when referred to social parts, the political party has always been conceived within the unitary logic of modern representation. For this reason, its primary goal has been the conquest of political power. Parties have been generated by representative democracy and by the enlargement of suffrage; however, the "Parteienstaat" is responsible for a series of aporias within the pillars of modern constitutionalism, especially regarding the separation of powers, the prohibition of imperative mandate, and the legislative and control function of Parliament.