By Mark Willen, Senior Political Editor June 4, 2008 Barack Obama woke up this morning facing one huge political problem: What to do about Hillary. By withholding her endorsement and encouraging her supporters to push her for the No. 2 slot on the ticket, she's not making life any easier for the presumptive Democratic nominee. Like everything else in this campaign, this is unprecedented. The normal, polite, respectful and politic thing to do is to let the presidential nominee savor his victory and take his time picking the best possible running mate. It is, after all, his first major decision, and it will say a lot about how he plans to run the government if he's elected. And it's generally seen as unseemly for a candidate to publicly seek the slot. But Hillary Clinton is having none of that. She said nice things about unifying the party last night but pointedly stopped short of endorsing Obama. A few hours earlier, she told the New York congressional delegation that she was open to the vice presidency, a comment she knew would immediately be leaked. She also let her staff leak word that she wanted the slot. And this morning her supporters were all over the talk shows pushing that prospect. There are plenty of good reasons for picking Clinton as his running mate (and plenty of good reasons not to), but Cliinton's selfish campaign for the slot makes it all that much harder for Obama to pick her. If he wants her on the ticket, he now has to come up with a way to do it that makes it clear it was his decision, not something he was forced into doing. That will be tricky. He also has to make it clear to Clinton that this will be his campaign -- that there can only be one presidential candidate, and if he wins, only one president. That also means defining, within strict limits, the role of Bill Clinton in the campaign and in an Obama administration. An even bigger problem awaits Obama if he decides against picking Clinton. He'll have to find some other way to placate her and her supporters, whose enthusiastic help he obviously needs for the fall campaign. With millions of her backers, especially women, already feeling they've been dissed by Obama, that will be no easy task. Even if Obama decides to put another woman on the ticket, many loyal Clinton supporters might say, nice try, but no thanks. Clinton may keep promising to work for party unity, but so far she's doing just the opposite, putting her own interests ahead of the party and the man it has chosen to lead it.