I ask again, "Why should he"?
If he's a certain loser -- as I would agree he probably is -- it would be a simple matter to play a delay game. Obfuscate the terms of the debate, its location, its timing, the format, the moderators, the context, etc.
The MSM would never question him in this regard. Instead, they would blame the Gingrich campaign -- for being "obstructive", "contentious", "uncooperative", etc.
Sure, our side would call him on it. They would taunt him and mock him. But would it cost Obama a single vote?
I think not.
If recollection serves, the last president able to avoid debate was Nixon with McGovern- But, Nixon knew that he had an insurmountable lead- and he used the excuse that it was a time of war. So, you’re right, to the extent that it doesn’t hurt Obama in the polls, he could avoid it.
In fall 2012, the economy could be great and all could be well internationally and people could be very happy with Obama’s America- and therefore, he could sidestep a debate.
But, if conditions are not as described, he can’t be perceived as the president afraid to confront his challenger- no matter how he or the media spins it.
IMO, there will be debates.
Newt has already announced he will simply appear everywhere Obama does an hour later ... and do a point by point tear down of everything Obama said in his speech. After a few stops like this where Newt always gets the last word, Obama will stop running away from debates.