sharyl: a bit later in the program, i'll ask trump a few questons posed by some of our could be a history making event. scott thuman takes a look at the history of presidential debates to see how they could make or break a candidate. whatcha' doin? just checking my free credit score at credit karma. what the??? you're welcome. i just helped you dodge a bullet. but i was just checking my... shhh... don't you know that checking your credit score lowers it! just be cool. actuly, checking your credit score wi credit karma doesn't affect it at all. are you sure? posi oooh "check out ckadirma today. creditarma. give yourself some credit." sorry about that. sharyl: 73% of all registered voters in the u.s. s theplan to tune into the debate tomorrow night. and that doesn't include a big number of non-voters who will watch in fascination from the sidelines. of debates, george w. bush once said, "i don't think you ever win them, but you darn sure can may prove pivotal. on the history of must-see political tv. >> good evening. scott: on september 26, 1960, more than 70 million america tuned in to see