John Edwards won almost half a million votes on Super Tuesday, more than enough to have tipped several states in different directions than they went in the close race between Barack Obama and Hillary Clinton for the Democratic presidential nomination.

That was a small measure of the lingering influence of a former candidate on a race that now heads toward two more states where the populist appeal of the Edwards campaign resonated.

So Barack Obama jetted out of Wisconsin, where he is battling for a big victory in Tuesday’s primary, for a Sunday meeting in Chapel Hill with John and Elizabeth Edwards. The Illinois senator left reporters behind to make what he hoped would be a secret trip, but a North Carolina television station was tipped off and got footage of Obama leaving the home where he met with the Edwardses.

Obama asked for an endorsement. But he also provided the former senator and his wife with detailed arguments about why he would be a stronger Democratic candidate in November, and an outline of how he would seek to implement progressive economic reforms as president.

A key part of the discussion focused on a priority of John Edwards: writing a Democratic platform that outlines a genuine change agenda.

“The meeting with John, we just wanted to talk about how we can move the party in a direction that focuses on middle-class issues, relieving poverty, reducing the influence of special interests in Washington,” Obama acknowledged Sunday night.

The trip comes at an essential time for Obama’s campaign, and illustrates how very much he wants the Edwards endorsement.

Obama has framed his Wisconsin campaign against Clinton as a fight over trade policy, but Obama’s record is not a whole lot better than Clinton’s on this issue. Edwards, who ran for the Democratic nomination this year as an ardent advocate for fair trade policies, has earned credibility with key unions — especially the United Steelworkers and to a lesser extent the United Auto Workers.

If an Edwards endorsement were to help break loose endorsements from those two unions, which remain powerful players in Ohio, it would be a dramatic boost for Obama.

Additionally, Edwards remains a particularly popular figure in rural and southern states. In Oklahoma, for instance, the former senator took more than 10 percent of the vote on February 5, after he had withdrawn from the race.

Parts of Oklahoma are a lot like parts of Texas, and Obama would love to have Edwards take a swing through the Lone Star state before the March 4 primary.

Will it happen?

When he was still in the race, Edwards was clearly more sympathetic toward Obama than Clinton. And the sentiment holds.

But the leap from sympathy to support has proven a long one.

By all accounts, the discussion inside the Edwards home revolves around whether Obama is ready for the presidency. Additionally, both John and Elizabeth Edwards are concerned that Obama’s health care plan is weak — especially in its failure to commit to universality. Clinton has played on those concerns during meetings with the Edwardses and phone conversations with them.

The Wisconsin primary result could be key. Edwards knows the state well; he almost won its 2004 primary and had many backers in the state this year, most of whom are now with Obama.

If Obama wins Wisconsin Tuesday, especially if the win is by a wide margin, that could finally tip Edwards toward the Illinois senator. By the same token, if Clinton were to win — or at least make it close after being somewhat written off in the state — watch for a new round of campaigning in the Edwards primary.