A lot of the commentary about the national and state polls that are shifting away from Mitt Romney focuses on his various missteps — the response to the Embassy attacks, the freeloading 47 percent remarks — as major causes of his political travails. And those are probably important.

But those don’t explain why Obama’s approval numbers, and his numbers on the economy in particular, seem to be visibly improving. Which suggests another possible explanation for all the movement: There may be stuff happening in the economy that hasn’t registered in the national jobs numbers political reporters and commentators focus relentlessly upon, but could easily be driving voter sentiment.

This is, of course, largely speculative. But consider: Obama’s national approval is at 51 percent in Gallup, and while it’s bounced around a bit, it has hovered at or around 49 and 50 percent with some regularity. In a host of the national polls, Romney’s advantage on the economy has evaporated entirely. One national survey even found Obama with a commanding lead among those who don’t believe their lot has improved. In Ohio and Florida, Obama is now leading Romney on the economy, and majorities now believe the economy either is improving or will improve if Obama’s policies are given more time. And so on.

So it’s possible that something is happening in the economy that we have not seen in the key indicators the political world watches. I asked Jared Bernstein, a former White House economist who is now with the Center on Budget and Policy Priorities, if there’s a potential explanation.

Bernstein cited “home price indexes,” which he says are “all percolating up.” He adds that voters may be feeling “the stabilization of the housing market, which is increasing home equity and the opportunity to refinance,” and says we may be seeing “some momentum in the job market in some of the key states,” where unemployment is lower than the national average.

“If you look at Ohio, it’s not just that they’re below the national unemployment rate, it’s that they’ve fallen farther, from being higher than the national average,” Bernstein says. “This is largely about momentum. It makes a very big difference whether you’re sailing into a storm or whether you’re sailing out of a storm.”

Again, we don’t yet know if this interpretation is true or not. But it’s one possible explanation for what is beginning to look like a real shift in the polls. And it’s worth keeping in mind, particularly since the political world is all but certain to fasten on the September jobs numbers as the only indicator that really matters.