Just in the last few weeks Barack Obama has lost four serious contenders for VP: Ohio Gov. Ted Strickland and Virginians Sen. Jim Webb and former Gov. Mark Warner, and RI Sen. Jack Reed. If these candidates didn't bring so much to the ticket, then it probably wouldn't be much of an issue. But all four carried very good arguments with them, not least of which is the fact that three of them could bring victory for Obama in two crucial states. Reed, who was a consideration for about half a second, in hindsight looks like a solid pick, with the one big disadvantage being that he brings no regional support to the ticket.

So far John McCain hasn't seen any refusals from his short list of candidates. We can count a few out at this point, but McCain is basically playing with the same set of choices he's had since clinching the nomination.

But the difference here raises an interesting question: Just why are Obama's choices backing off? With everything seemingly pointing toward a Democratic victory in November, including a larger majority in Congress, it would seem that an Obama administration is on the brink of history. What Democrat wouldn't want to be a part of that? To answer the question, those Democrats who don't relish giving up what power they currently have for something less than a "warm bucket of spit," as the VP office has been infamously termed.

But the VP race is more than just a parlor game to occupy journalists in the dead of summer. With the noticeable exception of Vice President Cheney, recent history shows that the VP is automatically heir apparent to the party. It is a big deal. So when a potential running mate takes himself out of the game, what he's also doing is taking himself out of the presidential race down the road. I don't think we'll see another Cheney, in terms of vowing to have no presidential ambitions, this cycle.

With Obama's diminishing short list, let's make a prediction: Despite the denials all around, Hillary Clinton as VP is an idea that I think has weathered the tumultuous month following her defeat. Polls show Democratic voters still like the idea and Clinton's electoral strengths certainly haven't lessened any. The big X factor is Bill, who, despite his own political strengths, is probably a net loss. Still, an Obama/Clinton ticket is very much a possibility.