I've always found the "to protect and serve" on police cars to be intensely ironic considering that they do neither.
Modern police serve mainly to try to keep the peace and to clean up after crimes. They come into most situations and arrest whoever is causing the most ruckus or is most uncooperative. They act like frustrated, tired parents who just want some quiet when they come home from work. Right and wrong mean a lot less then just getting everyone out of their hair.
Then comes the counselor act, where the cops show up after a crime. They assure everyone the that criminal will be caught (rare unless they are caught in the act of another crime) and clean up the mess a bit after pretending to care for a bit.
I'm sure my contempt for the police shows in this post, but I really do believe that as a whole we need more control of the people we allow to walk among us with guns.