As the U.S. presidential race heats up this summer, we’re covering some of the more interesting ways that new web technology is having an impact on it. The latest tidbit, that at least our politically-focused readers might care about, is a presidential debate to be staged on Twitter starting tonight.

Here’s how it will work. Feisty political blog Wonkette founder Ana Marie Cox, now an editor at Time magazine, will moderate the debate by posting a Twitter message (a “Tweet”) each day that contains a new question for the candidates.

But it’s not the candidates themselves doing the Twittering, but rather their selected representatives — neither of whom appear to have used Twitter until very recently. Republican National Committee communications director Liz Mair will be representing Republican candidate John McCain. Georgetown professor and former Clinton White house tech policy advisor Mike Nelson will be representing Democratic candidate Barack Obama. They’ll each respond to each tweet, with Cox presumably grilling them with follow-up tweets when they deliver weak-sauce responses.

Candidates will be allowed post multiple tweets — hence the “debate” part. They’ll also be allowed to link to web sites via tweets, a common practice for Twitter users. Linking seems like a potential loophole, though, as it could allow the debaters to link to press releases and other boring material instead of answering the question on Twitter. Let’s hope Cox holds their feet to the fire.

You’ll be able track the debate by following each person on their personal accounts. Cox is @anamariecox, Mair is @lizmair and Nelson is @mikenelson. Representatives will be using the hash tag option, tagging each of their responses with #pdfdebate, which will allow you to track the entire debate on Twitter Hashtags site. You can also use Twitter conversation-tracking service Summize.

The debate is an initiative of the Personal Democracy Forum (PdF), which is organizing a conference next week on the intersection of technology and politics. See more on the organization’s TechPresident blog.

The debate isn’t slated to end until, as with all Twitter conversations, the people doing the tweeting feel like stopping.

Oh yeah, and you can find me on Twitter here along with fellow VentureBeat writers MG Siegler, Dean Takahashi, Anthony Ha and Chris Morrison. We have a VentureBeat account (for our posts) as well.