If you fear human nature, you must fear government, because it rewards the worst in human nature while offering incentives to twist even the best intentions toward evil. @badquakerdotcom serialized a book called Authoritarian Sociopathy that goes into great depth on the nature of power and its effect on human psychology.

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6

A Jeffersonian Republic is no more sustainable than Marxist Communism. Look where it got the US in barely over 200 years.