And that's that

The Field appears to have a scoop:

The Field can now confirm, based on multiple sources, something that both campaigns publicly deny: that Senator Clinton has directly told Senator Obama that she wants to be his vice presidential nominee, and that Senator Obama politely but straightforwardly and irrevocably said “no.” Obama is going to pick his own running mate based on his own criteria and vetting process.

You can understand Hillary's peevish tenacity: she knows that the Democratic candidate has an excellent chance to win the White House this year and why not her? The best answer is that, as George Will notes, Americans are forward-looking and all Hillary offers is nostalgia for the (Bill) Clinton years.