For some time now, I’ve been tracking the polling numbers among blue collar whites, a key swing consistuency. After Obama did reasonably well in 2008 among them for a Democratic presidential candidate, Dems lost them in huge numbers in 2010 — and Obama needs to repair relations with them in order to win reelection. As Ronald Brownstein put it recently: “it would be a mistake for Democrats to underestimate the depth of white blue-collar alienation from the president.”

That’s true, and the attacks on Mitt Romney’s corporate background, low tax rates and offshoring are all about rendering him an unacceptable alternative to Obama among this key consistuency.

Today’s Post poll finds that Obama’s approval numbers among overall Americans are rising.

And so, I asked the Post polling team for a breakdown of Obama’s approval rating among non-college whites, and it appears he may be making some headway in winning them back:

For a larger version, click here. As the chart illustrates, Obama’s approval rating among these voters is 43-54. While those numbers don’t appear too good at first glance, things are trending Obama’s way. This is his best level among non-college whites since early last year (excluding the post-Bin Laden bump), and they are far better than they were at their lowest point in 2010, when Democrats suffered massive desertions among this constituency. This uptick coincides with signs that the recovery is strengthening, as well as with Obama’s new populist emphasis on tax fairness, inequality, and all the ways the economy is rigged against the middle class.

According to a recent report by the Center for American Progress, Obama only has to limit his losses among this group to win reelection. If can win white college graduates at roughly his 2008 levels, he can still win reelection with a big deficit among blue collar whites; if he can hold his losses among both groups to around John Kerry’s 2004 levels, he can also win.

(Caveat: In the Post poll, Obama’s numbers among blue collar whites on the economy in particular are still terrible, at 30-68, though his overall approval is rising.)

Also: Impressions of Romney’s wealth and whether his corporate work created or cut jobs are almost exactly split among blue collar whites. With large blocs of them undecided, the battle to define Romney’s past among these votes will be absolutely crucial.

But a big majority of blue collar whites, 67 percent, says that Romney’s not paying his fair share in taxes, suggesting Obama’s emphasis on tax fairness may be helping him make some headway in winning them back.