Being a politician is an forgivable sin, punishable by immediate death, at anyone's hands, with no necessity for a trial, accusation, or warning. No due process, just a do act.
Did you mean "unforgivable sin?"
I don't know whether being a politician is a sin or not. Is it a sin for a fish to swim or a bird to fly? Perhaps politicians are politicians simply because God chose to leave something important out of them when he created them, and it's not to be held against their account at all. After all, I have to believe God doesn't hold retarded people to account for not being smart.
But if it's a crime to take something that belongs to somebody else without his permission, and being a politician implies being paid with taxes, then being a politician is essentially a crime, yes, if not a sin. The only reason it's not popularly called a crime is the popular legitimization of the State's monopoly on the initiation of force.
Of course, the vast majority of politicians in the real world are guilty of far more than just extortion. There aren't many offices you can get into these days without giving your integrity to somebody.
"But whether the Constitution really be one thing, or another, this much is certain--that it has either authorized such a government as we have had, or has been powerless to prevent it. In either case, it is unfit to exist." --Lysander Spooner, 1867
