Natural Law and Sin Nature

A couple of years ago I discovered the "Uncle Eric" books by Bluestocking Press. They are totally amazing. They have helped me understand politics, government, inflation, the economy, etc. The books take the perspective of juris naturalis - which means natural law. I think everyone should read them. The two standards for living under this natural law are this (in my words):

1. Do all that you have said you will do
2. Do not encroach on others or their property

I love these standards. I think they are excellent in that they basically reflect the core of the Ten commandments. The "Uncle Eric" books are not spiritual per se, but they do point to the governing law under which we all live - and a strict adherence to right and wrong. As a Christian, I believe wholeheartedly that this standard comes from God. He has it outlined in His word over and over again. The problem with living in accordance with natural law is this - the sin nature. Even if I abide by these principles, if others don't, there is a conflict. However, we know that the fallen world surrounds us and the sin nature is in us all. So there are none who can live perfectly under the governing of the natural law, apart from Christ.
I was thinking about this the other day when we were watching some episodes from the first season of LOST. (I do not typically watch much television but this one came recommended - thanks Karen!) A group of 40 some people survive a plane crash and are stranded on a deserted island. They go about making a "community" among themselves as the chances of being rescued appear slim. At one point they realize an intruder - someone who was on the island before they were - has infiltrated their community - and start taking inventory of who was on the plane - comparing personal information from each individual and comparing it to the flight manifest. Hurley, the self-appointed statistician, initiates this beginning form of "island government", and one of the other island members accuses him of imposing his own brand of the "Patriot Act". However, it was this check that was done that helped them find the intruder in their midst. The truth of the matter is that while often we are resistant to the restraints of government, and the privacy and freedoms that we have to give up, we all want to know about the other guy. It really made me think.

So while juris naturalis may indeed be an excellent standard to live by, as are the Ten Commandments, who can do it?