Colorado has a "Make My Day" law - where if they're in your home without authorization and posing a clear threat to you/family/etc.. You can control the situation as needed. There's probably more info on this that I have... It seems to play itself out in Downtown Denver most frequently from what I recall. I don't think shooting the paperboy in the back after giving him a cup of coffee while he leaves your home qualifies.
MD.
MD.