"A democracy cannot exist as a permanent form of government. It can only exist until the voters discover that they can vote themselves money from the public treasure. From that moment on the majority always votes for the candidates promising the most money from the public treasury, with the result that a democracy always collapses over loose fiscal policy followed by a dictatorship. The average age of the world's great civilizations has been two hundred years. These nations have progressed through the following sequence: from bondage to spiritual faith, from spiritual faith to great courage, from courage to liberty, from liberty to abundance, from abundance to selfishness, from selfishness to complacency, from complacency to apathy, from apathy to dependency, from dependency back to bondage."
Alexander Tyler
Unfortunately the same applies to Republics(only it take more time), when the reigns of government lay in the hands of a small number of political factions(i.e. Parties) electing representatives on the basis of stands on issures as opposed to the moral capacity of the office holder.