Politico is reporting this morning that aides for Barack Obama and Hillary Clinton are still resentful of each other and that the choice of Joe Biden as running mate hasn't helped matters any.

The two sides continue to take anonymous swipes at each other in the meda:

A prominent Obama backer said some of Clinton's lieutentants negotiating with the Obama team are "bitter enders" who presume that, rather than the Clintons reconciling themselves to Obama's victory, it is up to Obama to accommodate them.

In fact, some senior veterans of Clinton's presidential campaign do believe this.

"He has not fully reconciled," said one political operative close to the Clintons, "and he has not demonstrated that he accepts the Clintons and the Clinton wing of the party."

While the Clintons have a relatively easy job in Denver - to deliver gracious speeches and accept what are likely to be loud cheers from their supporters - it is "Obama who has the heavy lifting" this week, this aide said.

This is because large numbers of Clinton backers - 30 percent in a recent ABC/Washington Post poll - are still not backing Obama over McCain.

Historically, that is a very high number of defeated partisans to be talking about supporting the opposition or not voting at all. But given the polarizing times we live in and the way the Democratic primaries were conducted, it shouldn't be surprising at this point that a sizable percentage of Hilalry supporters are resisting Obama's call for unity.

Then again, many Hillary supporters are conservative, working class ethnics in states like Pennsylvania, Ohio, and Michigan who would have trouble supporting a liberal candidate like Obama anyway. McCain is targeting these voters and may be able to pry a nice chunk of them away from the Democrats in November.

Enough to make a difference in Pennsylvania, for example? I think if McCain can keep from making expensive gaffes, the answer to that question is yes. These voters are inclined to support McCain anyway and Obama's liberalism and the way his campaign treated Hillary Clinton only makes it a little easier.

But McCain will not get 30% of Hillary supporters nor 20%, nor is it likely he will receive 10%. The historic average is about 4% and I think he could do better than that. But in the end, most of those Hillary supporters will indeed vote for Obama - or stay home on election day.