In his classification of political systems, Montesquieu defines three main kinds: republican, monarchical, and despotic. As he defines them, Republican political systems vary depending on how broadly they extend citizenship rights—those that extend citizenship relatively broadly are termed democratic republics, while those that restrict citizenship more narrowly are termed aristocratic republics. The distinction between monarchy and despotism hinges on whether or not a fixed set of laws exists that can restrain the authority of the ruler: if so, the regime counts as a monarchy; if not, it counts as despotism.