I want to bring in abc news political analyst matt dowd who has advised both republican and democratic campaigns. Matt, as always, it's great to have you with us. You have three ts for everyone to... See More
I want to bring in abc news political analyst matt dowd who has advised both republican and democratic campaigns. Matt, as always, it's great to have you with us. You have three ts for everyone to watch for. One of the things you point out, body language could have a bigger impact than words. We remember al gore and george bush and jon stewart having a field day with those. I've had a record of that in texas. As if the sighing weren't bad enough, gore's behavior got worse. in that same year we remember that moment when al gore got up, walked over towards then governor bush, and this was his reaction. Trying to get things done. And I believe I can. famous moments. Years prior there was h.W. Bush checking his watch at the debates. These have become famous moments. Are these debate prep teams saying this is what you don't do? At this point in time they're emphasizing style as opposed to substance right now because debates that have changed people's minds have all been about physical characteristics and mannerisms really in the modern age and not about the substance of the policy answers, so they're paying a lot of attention to the style and not the substance. You can almost watch the debate with the volume down and determine who wins this thing. You pointed out something else, you were at the next debate. This was an image from senator kerry taking on george w. Bush and say by simply showing up, the challenger has a lot to gain. Yeah, when they stand on the same stage as the president of basically become almost an equal at that point in time and that race went from a seven-point lead to a one-point lead in 48 hours and that's what the challenger was able to do. John kerry won it and took the race to almost even within two days. So a big opportunity for mitt romney this week. Huge opportunity for mitt romney. He could take this race in the states he's losing right now and change the dynamic of this race just by standing on stage and performing well. So much riding on it. This first debate, anywhere between 50 million, 60 million viewers are the estimates. This year more important than ever the early voting that's taking place. Early voting has taken place in key states like iowa right now and voters willing watching this. Already voting and the best thing about this debate is -- fore these guys, it's the first authentic moment in a while where voters want to tune in and pay attention. It's not a television ad, it's not a convention but a real authentic moment they take cues from. By election day a third of american voters might have already gone to the poll. Campaigns used to have to plan toward one election day and now they can plan toward 30 or 35 election days, and that's why this debate is crucial because voting is already going on. Matt dowd with us in new york. Matt, our thanks to you and special coverage "one on one" wednesday 9:00 p.M. Begins at 9:00 p.M. On wednesday night. Diane and george. I'll be in denver with jake tapper and the entire political team here wednesday night.
This transcript has been automatically generated and may not be 100% accurate.