Okay, this is probably a little bit dick-ish at some level and is about as realistic as me being the President of Antarctica, but I just had goofy thought.
Wouldn't it be great, if, in response to John McCain's demand to a townhall debate, Barack Obama sets one up... between him and Bob Barr of the Libertarian Party, while freezing out the GOP?
You know, Bob Barr, the ex-GOP representative, the one who was so disgusted with the GOP that he left the Party?
Think of the putdown value: you can bill this as a debate between a "True(tm)liberal and a True(tm) conservative". And you can honestly call it as such: it seems entirely feasible that either candidate would concede points on the margin-whether this relatively unimportant activity calls for more government or less, instead of the "OMG where's your lapel pin?!" nonsense.
Of course, a debate between the two will not obscure the fact that True(tm) conservatives and True(tm) liberals will call dumb war for what it is, as well as its enabler. It's a win-win situation for both the Libertarian Party and the Democratic Party, both coincidentally at the expense of the GOP.
The imagery of the GOP looking bad trying to smear the Libertarian Party as being insufficiently conservative fills me with premium grade schadenfreude