He's always had a target on him by progressive neerdowell's, and he has survived them all, including the likes of the loathsome O'Bongo Regime and Holder's Henchmen...they no doubt failed because they could not infiltrate his organization and create the evidence they needed to manufacture.
Problem is, I hope Joe has some good deputies that can succeed him, because he ain't a spring chicken any more, heck he ain't a late fall chicken either!