"A democracy cannot exist as a permanent form of government. It can only exist until the voters discover they can vote themselves largess from the public treasury. From that moment on, the majority always votes for the candidates promising them the most benefits from the public treasury, with the result that a democracy always collapses over loose fiscal policy, always followed by a dictatorship." - two quotations, attributed to Alexander Fraser Tytler, but not verified.
The average age of the world's greatest civilizations has been 200 years. These nations have progressed through the sequence below. This progression has been called the Tytler Cycle, but I cannot find a primary source to connect it to him. I have provided the cycle and dates I connect to American history.
From bondage to spiritual faith (1600s to 1770)
From spiritual faith to great courage (1770 to 1785)
From courage to liberty (1785 to 1865)
From liberty to abundance (1865 to 1970)
From abundance to selfishness (1970 to 1990)
From selfishness to apathy (1990 to 2010)
From apathy to dependence (2010 to ????)
From dependency back again into bondage