I hear that automatic/assault weapons are made to do one thing. To kill lots of people. So why do police need assault weapons? To protect and serve? Disarm the police, and I will disarm. Not really, but you get the point.
IMO, the biggest potential threat to American citizens is the trigger happy police and the laws & procedures that protect them. I have some substantial fire power to protect myself from those who have lots of guns, like the police.