Why not just let any U.S. citizen get up there and rant on national TV? It would be just like the drunks and homeless who get on the NYC subways and rant to a captive audience.
Er... let me guess... because these are supposed to be debates between Presidential candidates? What are you so worried about? If these guys are such kooks, George and John oughta be able to make them look like idiots with no problems right?