I have been asked repeatedly about my assertion that democracies/republics are short lived propositions. When we think of the inspirations for modern democracies or republics, we naturally think of Athens and Rome. If one were to date the democratic experiment in Athens, the earliest possible date would be Solon in about 594BC until the experiment was suppressed by the Macedonians in 322BC. A very generous estimation would then be about 300 years. (By way of comparison, the British monarchy is well over 900 years old.) The Roman republic (not the state) was founded in 509BC with Lucius Junius Brutus as one of the first consuls. The end of the republic is tougher to pin down. By anyone's estimation it was dead when Julius Caesar crossed the Rubicon, 49BC, approximately 470 years. (The Bourbons ruled France for almost one thousand years.) These are the most generous dates imaginable. Most historians would say too generous by half.
Now there have been other attempts at these forms of government before the American experiment, but they have been on very small scales or not really democracies/republics at all, one thinks of the Swiss cantons or perhaps some tribal systems. When we consider this form of government in a historical context we must look to Athens and Rome. If we took our inspiration from them, we might be wise to keep an eye on how they progressed and ended. When they had become wealthy, successful and dominant, they also became lax and decadent. Both ended in despotism, Rome of the home grown variety and Athens of the conquering variety. This is why Benjamin Franklin, when asked what form of government the new Constitution was, said, "A republic, if you can keep it." He knew his history unlike most moderns.