Need helping thinking of this movie...?

I have to write an essay comparing the graphic novel "The Watchmen" to a movie. I wanted to focus on the aspect that society grew to resent the Watchmen, but in reality they were working to better the world. I am looking for a movie who similarly has a group, or an individual, that their community does not like but they actually are trying to improve society. I can't think of anything. Help please?