Corruption

Comrade Misfit put up a post about the criminal behavior of some cops in Philadelphia. The story is pretty bad, so bad that it reminded me of a movie about corrupt cops in Rio De Janeiro, Brazil, which I think has got to be saying something.
    Thanks to the internet there is constant stream of these stories available to fuel our outrage.  Problem is that corruption has always been with us and it looks like it always will be. Something about human nature, I suppose. My question is when does it become too much? When do you say I've had enough and pick up your pitchforks and torches and march on town hall?
    I read something recently that said countries with effective democracies don't have riots like we see in other countries. We do have democracy here in USA, but I suspect that at the national level it has become simply a circus to keep the masses entertained. Nothing changes, the poor stay poor and the rich get rich.
    Nazi Germany continues to garner a great deal of attention. Sometimes I get tired of hearing about it, but it is a startling example of how the best of intentions can lead straight to hell. Many people are predicting dire consequences if we continue our current policies.
    Nobody knows what the future will bring. The most innocuous of things could have tragic consequences for millions of people. The most frightening government policies could result in widespread happiness and contentment. Unlikely, I know. The point is that you can never tell what the outcome will be. You can make predictions and gauge probablities, but that's about all.
    Back to my main point: how can you tell when the level of corruption has become a real problem, and what do you do if it has?