The big federal report on cratering middle class wealth in 2007-2010 is really a reminder of something that has gotten lost in the daily back and forth: This presidential election is highly unusual, and both campaigns are, in a sense, making it up as they go along.

It’s actually rare for a new president to take office during a recession, and rarer still for one to take office amid a horrific crisis, as Obama did. Bill Clinton, Ronald Reagan, and Jimmy Carter took office soon after recessions technically ended. But Obama’s case was different; his inauguration was right at the deepest point of the downturn. And of course it was a far deeper recession than any of those others. That’s not all: the Obama recovery, although real, is a lot less impressive than most comparable periods after recessions.

Here’s one way to think about this: Obama’s chances for reelection are going to depend heavily on whether the American people hold Obama or George W. Bush responsible for the economy. In effect, this is essentially a matchup between Obama and his predecessor in a way we haven’t seen in presidential elections before.

The highly unusual nature of this election means that there will be whole lot of uncertainty about how economic “fundamentals” play, and they may play in a new way. One political scientist finds that election prediction based on the fundamentals finds that the first year’s economic performance works backwards, with a worse economy in year one helping re-election. If that’s true, it makes Barack Obama a likely winner this year…but then again, there’s really no way to know for sure whether it is true.

That’s why so many of the campaign messages you’re going to hear this year come down to the argument about whether Barack Obama should be rewarded or punished for the current state of the economy, which boils down, in large part, to that Obama vs. Bush question. In some ways, that’s frustrating for many analysts, who might point out that logically, what voters should be comparing are the plans that Obama and Mitt Romney have for the future.

And, perhaps, voters should do that. But it’s unlikely they will. Swing voters, especially, tend to be politically indifferent and inattentive, and so they’re not very likely to even know what the candidates plan to do if elected, and even less likely to try to evaluate those plans.

So certainly you can expect more skirmishes over the candidates’ platforms, and perhaps even some serious debate about issues such as whether state and local governments should be spending more or less right now. But the overriding imperative for the Obama campaign has to be to push voters to see the current economy, weak as it is, as much better than the one he inherited from Bush. Meanwhile, the overriding imperative for Team Romney has to be to induce as much amnesia as they can about how — and when — all this trouble started. Whoever wins that messaging battle will probably be the next president.