We’ve talked a lot about “the fiscal cliff.” But the Congressional Budget Office’s report on the subject estimates what you might call “the fiscal plain” scenario: The world in which we extend all the tax cuts, put off all the spending cuts, etc. The economy, they say, would grow by 4.4 percent next year.

That sounds fairly optimistic to me. But let’s assume, for a minute, it isn’t, and that it actually happens. Then either Barack Obama or Mitt Romney, without introducing any major new policies of their own, would be presiding over 4+ percent growth. Politically, that would be huge for them and their party. The midterms would likely be a cakewalk -- you don’t want to change horses mid-gallup, do you? And it would likely have the effect of legitimizing whatever their platform was.

If it happens under Romney, Republicans will use it as evidence that policy uncertainty from health-care reform, and Dodd-Frank, and future deficits, was really behind the slow recovery. And if Obama is in office, it will be used to show that he -- and Keynesian fiscal policy -- guided us out of a difficult recession, and once Republicans stopped threatening to shrink the economy, we roared back to growth. barring an intervention from the Supreme Court, the health-care law will be implemented, and so too will Dodd-Frank, and Obama’s legacy will be assured.

This is very much the scenario I’m talking about when I say that the 2012 election is unusually important. Whoever wins it is likely to preside, as an accident of timing, over quite a bit of the recovery, and their program is likely to look pretty good because of it. This is what happened to FDR during the Great Depression, what happened to Ronald Reagan after Paul Volcker broke inflation and then unleashed a boom, and it’s probably going to happen to one of the two parties in the coming few years. Policy matters, but so does being around when policy leads to a recovery.

Of course, if we do hit the full fiscal crisis scenario, and we add a debt-ceiling crisis on top of it, things will get much worse before they get any better.