The issue of presidential debates can be contentious, which is why there’s a Commission on Presidential Debates, which is supposed to take some of the politics out of it. The CPD has already picked four locations and dates (three for the presidential candidates, one for the VP candidates), which were selected long before anyone knew who the candidates would be.

One assumes John McCain will agree to the schedule, but today, he will renew talk about adding to the existing slate of events.

John McCain will use the first day of the general election to propose additional debates or joint forums beyond the three sanctioned for this fall, according to a McCain source.

At a town hall meeting and press conference in Baton Rouge later this morning, the Republican nominee will make his case for why there should be more engagement between he and Barack Obama.

The first presidential debate is scheduled for September 26th in Oxford, Mississippi, but McCain would like to set up a series of joint appearances.

One such meeting could be just down the road from where McCain is making his case. A coalition of business and civic leaders in New Orleans, which was denied a sanctioned debate, have scheduled a presidential forum for September 18th.

I suspect there are going to be lots of Dems who think this sounds great, and there are, to be sure, some upsides to the idea. But let’s not get hasty here.

This issue first came up in April, when McCain aide Mark McKinnon (who later stepped down from the campaign because he respects Obama so much) suggested the two presidential candidates are respectful and high-minded enough that they could travel across the country discussing the issues of the day in a series of debates.

Obama warmed up to the idea rather quickly.

Democratic presidential candidate Barack Obama said he’d be willing to campaign jointly with Senator John McCain, the presumptive Republican nominee, and debate him in town-hall style formats.

“I think that’s a great idea,” Obama, 46, told reporters in Bend, Oregon, today as he campaigned ahead of the state’s May 20 primary. “Obviously we would have to think through the logistics on that, but to the extent that should I, should I be the nominee, if I have the opportunity to debate substantive issues before the voters with John McCain, that’s something that I am going to welcome.”

If there’s a perceived “stature gap,” debates help tremendously. Obama can stand toe-to-toe with McCain, and show that he’s more knowledgeable, about more issues.

But there are some real downsides to the idea. Noam Scheiber noted recently:

McCain has several big disadvantages vis-a-vis Obama. He faces a massive enthusiasm gap and will have trouble attracting large crowds. He’s in all likelihood going to be massively outraised and outspent, making it hard to get his message out. And, possibly as a result of the previous problem, he’ll be cast as a right-winger determined to continue George Bush’s policies.

The unmoderated debates would help him overcome all three problems. They’ll draw big crowds and generate lots of buzz. They’ll help him get his message out for free. And, just by virtue of appearing frequently at Obama’s side and having a civil debate, they’ll make him look much more moderate than the Obama campaign wants him to look.

I’d just add that I’m not even sure that Obama’s a better debater than McCain. Obama’s a better speaker, and a smarter leader, but debates aren’t necessarily Obama’s best format. He tends to think in paragraphs, while debates force participants to think in sound-bites.

Alex Massie argued a while back:

In the first place it flatters Obama’s already well-developed sense of himself as a statesman cut from a higher grade of cloth than that worn by other politicians these days. It appeals to his idea of “elevating” politics too. Thirdly, and relatedly, it’s easy to suspect that Obama could be weary of having to play the “gotcha” game favoured by the likes of Tim Russert, Chris Matthews and the rest of the blowhards who moderate “traditional” debates and, consequently, that he’d be open to anything that stymied their desire to referee the contest.

All true. And this no doubt helps explain why the McCain campaign started baiting Obama with the idea to begin with.

To be sure, these events wouldn’t necessarily be bad for Obama. If the discussions center on policy, Obama would no doubt welcome the opportunity to highlight the fact that on the issues people care about most, Obama is part of the mainstream and McCain isn’t. For that matter, McCain tends to come off great in town-hall meetings, but largely because no one’s there to point out how wrong he is. If he’s sharing a stage with Obama, McCain may enjoy himself far less.

But all things being equal, Obama might have more to lose. There’s a reason the McCain campaign is pushing the idea, and it’s not their love of spirited discourse.