Barack Obama had planned to veer off the “Potomac Primary” campaign trail after his last rally in Baltimore tonight and fly to Chapel Hill for a private meeting with John Edwards. Scheduling conflicts scrapped that scheme, but count on Obama to make a meeting happen in short order.

Obama wants the former North Carolina senator’s endorsement. Badly.

Why? Check this out:

On Super Tuesday, 415,000 Democratic primary and caucus voters chose John Edwards as their candidate for president. It is true that many of those votes came on “early ballots” that were cast before the former senator from North Carolina withdrew from the race. But hundreds of thousands of Democrats and independents who were motivated enough to go and vote on February 5 did so for Edwards, knowing full well that he was out of the running.

In Oklahoma, where Edwards might well have won the primary if he had stayed in the race, the former candidate won more than 10 percent of the vote. In several of the state’s larger counties, the 2004 Democratic nominee for vice president took second place, running ahead of either Obama or Hillary Clinton. In the state’s 2nd and 3rd congressional districts, Edwards took 13 percent of the vote, narrowly missing the 15 percent threshold needed to secure delegates.

In California, Edwards won 170,050 votes for 4 percent of the total. And in at least one of the state’s congressional districts he fell just short of the 15 percent threshold.

In Arizona, Edwards won 5 percent; in Tennessee, he took 4 percent.

In Louisiana, which voted on Saturday, Edwards continued to win as much as 5 percent of the vote in some congressional districts.

Does this matter? It did in Missouri, which gave Obama an essential win by just 9,997 votes. Edwards took 16,747 votes. Had the Edwards votes broken for Clinton, she might well have won another of the key battleground states on Super Tuesday.

Similarly, had Edwards votes flipped to Obama in a number of congressional districts across the country, the Illinois senator would have won more delegates to this summer’s Democratic National Convention. Take the 28th District on New York state, where Clinton beat Obama by 509 votes. That gave her 3 delegates to 2 for Obama. But if the 691 Edwards votes in the district had gone to Obama, he would have had the 3 delegates to Clinton’s 2.

Of course, no former candidate’s endorsement can swing all of his or her supporters behind another contender.

But both the Clinton and Obama camps have come to recognize that a nod from Edwards could influence a significant number of his former (and in some cases continuing) backers. And the remaining candidates know that in a close race for the nomination — after his Maine caucuses win on Sunday, Obama leads Clinton by 3 delegates — an endorsement could be definitional.

This is especially true right now, as next Tuesday’s big primary is in Wisconsin, a state where Edwards had the backing of Congressman David Obey, Madison Mayor Dave Cieslewicz and many key legislators and local officials.

So Clinton and Obama are making their moves.

Clinton rearranged her schedule to meet last week with Edwards in Chapel Hill. She then said while campaigning in Maine that, “There is a lot that John and I have in common… And I intend to ask John Edwards to be part of anything I do.. when I’m in the White House.”

Clinton does not necessarily expect an Edwards endorsement. She wants him to stay out.

Obama wants him in.

So watch for veiled references from Obama — think “Attorney General Edwards” — about how much he wants to work with the former senator.

And when should we expect an endorsement — or a formal decision to stay on the sidelines?

No doubt, there will have to be an Edwards-Obama meeting. But once that happens, expect a decision in short order. Edwards is not meeting with the candidates for fun. He knows that this is the moment when he matters most. He will move sooner rather than later.