“The deterioration of every government begins with the decay of the principles on which it was founded.” – Charles de Montesquieu (1689-1755)

If you have not yet read Spirit of Laws, I wish to highly recommend it.  An English translation of this seminal work on which many of the ideas of how government should best be worked under the rule of law can be found here for your reading pleasure and edification:

http://www.constitution.org/cm/sol.htm