Clinton campaign to steal Obama's delegates he won via the primaries?

There's a report from Roger Simon at the Politico - someone who Joe says is a "real" reporter, i.e., he doesn't just report unsubstantiated rumors - that a senior Clinton campaign official told the reporter that they are planning on trying to take Obama's delegates that he won in the primaries.

What does this mean? Take Virginia. Obama beat Clinton 64% to 35%. That gave Obama 54 delegates to Clinton's 29 delegates. The Clinton campaign is reportedly going to try to convince those 54 Obama delegates not to support Obama at the convention, even though you voted for those delegates to support Obama. We're not talking superdelegates - we're talking the delegates you voted for in the various state primaries. We're talking your vote.

Clinton's campaign says the story isn't true. This means that Roger Simon needs to now give his side of the story. Having said that, the Clinton campaign has gone increasingly negative in the past few days - accusing Obama of plagiarism (when Hillary herself has adopted Obama's "change" theme), and they've accused Obama of skirting debates when he's already done 18 of them and agreed to 2 more in the next few weeks (it's not clear why the Obama campaign didn't counter-offer a series of debates about Iraq and Iran - that would have ended the discussion). That doesn't prove that this story is true, but this delegate-stealing story is the kind of news that is consistent with a campaign that is sounding increasingly worried and is resorting to increasingly nasty tactics.

And putting all that aside, how is it even possible that our rules permit this?