Expect big debate audience

Interesting number from The Hill's new poll, conducted by Pulse Opinion Research: 85% of likely voters say they'll probably tune in to Wednesday's debate, while just 12% don't plan on it.

Now... the caveat is that history suggests the audience won't reach 85%, and it's understandable why many voters say they'll watch but actually won't. If you're a likely voter, you'll probably want to claim you're doing due diligence in choosing a candidate and some of that diligence is watching a debate.

Having said that, first debates do tend to have the highest ratings in the modern era.

According to Nielsen, the first debate was the most watched in the 1988, 1996, 2000, and 2004 elections, and in 2008, the first debate produced much more online engagement than the following two presidential debates.

Having said that, more watched the second presidential debate in 2008 than the first, which was actually the lowest rated of the three.

Overall, debate ratings have -- not surprisingly -- been falling since the advent of bountiful cable TV.

The largest debate audience in history was 1980's October 28 face-off between Carter and Reagan, which claimed 80.6 million viewers. Meanwhile, the highest rated was Kennedy and Nixon's October 13, 1960 debate, which scored a 61% rating.