The problem is, that (at least today's) societies need some kind of immune system. As much as I liked the world to be without arms, I see the need for law enforcement.

I see the need of a society for people making harsh decisions. Sometimes the utilitarian greater good needs the suffering of the few to come into existence.

The problem is, when it is turned on its head, so that the greater majority suffers a little bit (financially, or otherwise) for the benefit of the smaller minority. And that is, what our current system of lobbying/economics/politics sadly seems designed to achieve.

Actually to parent's point, it's ensuring that even if the worst people got into positions of power, things would be structured enough and there'd be enough checks to keep them from doing any real damage.

But I don't think this is a workable task in a political system. The views of the guy you voted for are going to be different from the one you didn't vote for. In a perfect system every person will be impartial in evaluating elected officials. In the real world, if you evaluate the guy you DID NOT elect you would be perceived as being biased. On the other hand, if you evaluate the person you DID elect you would be perceived as being biased as well. Both cases you would be perceived as being biased. So the only workable approach is to focus less on individuals and more on the system and its results.