The Social Contract by Jean-Jacques Rousseau

As the particular will acts constantly in opposition to the general will, the government continually exerts itself against the Sovereignty. The greater this exertion becomes, the more the constitution changes; and, as there is in this case no other corporate will to create an equilibrium by resisting the will of the prince, sooner or later the prince must inevitably suppress the Sovereign and break the social treaty. This is the unavoidable and inherent defect which, from the very birth of the body politic, tends ceaselessly to destroy it, as age and death end by destroying the human body.

There are two general courses by which government degenerates: i.e. when it undergoes contraction, or when the State is dissolved.