1) From a horse-race perspective, John McCain came in behind and losing ground, in the middle of a financial/economic panic that works against him, and therefore needing a big win. This meant either damaging and flummoxing Obama, or so outshining him in audience rapport, mastery of policy, and empathetic connection through the camera, that the debate could be presented as a turning point. None of that happened. (McCain's best performance was at the end, rejecting a "Yes/No" question on whether Russia is an "evil empire.") At this stage in the race, a tie goes to the leader, and this was not even a tie.
2) "That one." Difficult to discuss. Unwise (and unnecessary) for Obama or his campaign ever to mention themselves. But creates an impression that may be impossible to erase.
3) The betting had been, including from me, that this Town Hall format would best suit McCain -- the informality, the opportunity for jokeyness, the track record of handling such questions easily. To my eye, that betting turned out wrong, partly through McCain's doing and partly through Obama's.
On McCain's side -- to my eye -- this meant a range of references that collectively amounted to something like George H.W. Bush's weary glance at his wristwatch during his own Town Hall debate with the vigorous young Bill Clinton 16 years ago. The forced and unsuccessful Bob Hope-style jokes, the repeated reference to the "overhead projector," the prevalent allusions to an era much of the electorate considers past. Tip O'Neill, the early Reagan, the Marine disaster in Lebanon -- important all, but dated-sounding in 2008.