the basic truth is that they cant. No matter what form of government, political, or social system is imposed on the people. There will always be the extremes of two sides and those that are willing to push the limit and do anything to further their cause in their own eyes,whether they see it as a way to save humanity, to obtain power, to destroy some regime, or some other goal. That leaves everyone thats in the middle hanging, waiting for the final bang.
The central banks in tandem with the old monied families and nobility. These people operate through unelected bureaucracies which the politicians and so-called "elected officials" must answer to. Politicians don't work for the people, they work for the people who wield the real power behind the scenes. These are the people that put them in power and allow them to maintain their position, as long as they do as they're told. If they don't do are they're told, they find themselves in the middle of a massive scandal or they end up dead in some convenient "accident." We know what happened to Kennedy when he decided to go against his handlers.
Yeah and it's sad when someone who really might actually make change (maybe someone like Ron Paul even) gets brushed to the side in the elections. From what I've seen so far he's the closest Jimmi Carter we got right now.