This is one of the reasons why Europe and the United States are facing debt crises and political dysfunction at the same time. People used to believe that human depravity was self-evident and democratic self-government was fragile. Now they think depravity is nonexistent and they take self-government for granted.
Neither the United States nor the European model will work again until we rediscover and acknowledge our own natural weaknesses and learn to police rather than lionize our impulses.
Pretty much covers it. Recognize our natures are flawed and learn to compensate -- with check/balances, religion, culture, etc.
Unfortunately, I don't expect this enlightenment to be generally sinking in anytime soon.