WASHINGTON--Secretary of State Hillary Rodham Clinton tried to shutdown pundits who have been speculating that President Barack Obama could improve his re-election chances by dropping Vice President Joe Biden and making her his runningmate.

Clinton has already said she will step down from the Obama cabinet at the end of the term. NBC's Savannah Guthrie asked her about the political chatter of an Obama-Clinton ticket in an interview broadcast Thursday.

Asked if it is even "in the realm of possibility," Clinton said, "I do not think it's even in the realm of possibility, and in large measure because I think Vice President Biden has done an amazingly good job. He has taken on the burden of selling the economic plan, of traveling the country, of answering people's questions."

Clinton also said no one has ever raised it with her.

"It's maybe a subject for speculation on Google, but it's not a serious issue in the administration," she said.