Talk about holding a grudge.

Bill Richardson, energy secretary and U.N. ambassador under former President Bill Clinton, revealed that his former boss has held a six-year grudge against him for endorsing Barack Obama, not Hillary Clinton, in the 2008 Democratic presidential primaries.

Speaking to Larry King on, Richardson said, “He's still mad at me, you know, he's had differences with some of his former staffers, but so far he hasn't forgiven me.”

While personal breaches, he said, sometimes take a while to heal, Richardson said, “This one has been unusually long, but if he wishes to keep it separate and a breach, then so be it. I'm not uncomfortable. I'm not begging. I'm fine. I'm happy.”

Richardson said the rift with Hillary Clinton is still a problem too, and offered a chance to endorse her for president, he declined.

“I'm not one of these that feel like I have to suck up to anybody, I wanna see who the candidates are, I think there should be open competition, I know Hillary Clinton is a formidable candidate. It's not that I won't ever be there but right now, I'm not one of those hundred of Democrats flocking and saying the race is over,” he added on “PoliticKING with Larry King.”

But if she is the nominee, Richardson added, he would back her and not hold any grudge against the Clintons.

“If she's the nominee I would support her,” he said. “I'm not going to let this breach that we had stand in that way, but I'm also not gonna go after her and be like, ?I want to be on your team.' No. I like many other voters, I'd like to be convinced about her plans and vision about the country.”

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at