Best approach for admitted sinners??

In another thread it was noted that it is as rational to teach a 4004 BC creation date as to teach an old universe. But how does one with a "Biblical world view" conclude that we are rational? Are we not all liars?

Seems to me that when deciding upon the "best" political/educational/economic tack to take, the bottom line should be:

Which system (world view, type of government, scientific/historical approach) best compensates for our admitted sin nature? What is the best decision making process for a society of admitted greedy liars? How can we find a middle ground that minimizes our evil tendencies?