Washington, July 14 : Sources close to Democratic presidential nominee Barack Obama have said that Obama may not consider Hillary Clinton as his running mate because of her husband and former U. S. President Bill Clinton.

Bill, once his wife''s greatest political asset, is now being viewed by the Obama camp as such a liability, that he (Bill Clinton) is likely to end Hillary’s chances of becoming the Democratic vice-presidential candidate, reports The Telegraph.

Obama campaign sources indicated that Bill Clinton''s reluctance to disclose who has donated money to his presidential library and even concerns about possible extra-marital affairs mean that Hillary would not pass the vetting procedure that all potential running mates have to undergo.

"It is absolutely standard operating procedure that vice-presidential candidates today must be fully vetted," a Democratic official close to the Obama campaign told The Daily Telegraph.

"That means their finances and everything about them. Bill Clinton''s not going to submit to vetting. He has not released details of the contributors to his library or his personal finances. Everything has to be disclosed to the law firm overseeing this process," he added.

"There''s a questionnaire. It covers everything, including, ''Have you got any girlfriends?''"

Last week, Obama told a prominent supporter of Mrs Clinton that he viewed the former president as a "complication" that made it more difficult for him to choose the former First Lady, who has made clear she would like to be on the Democratic ticket with him.

"He said once you''re a president, even if you''re a former president, you''re always a president," Jill Iscol, a stalwart supporter of Hillary Clinton, told the Los Angeles Times.

There is little enthusiasm within the Obama campaign for selecting Hillary Clinton as a vice-presidential candidate. After a bruising primary battle, her loyalty to Obama is seen as questionable and there are concerns she could alienate centrist voters.

A Democratic strategist aligned with the Obama campaign said: "Despite the spin coming out of the Clinton campaign in the primaries, the Clintons have a very mixed reputation among independents and moderate Republicans, who are the people Barack Obama needs to convince to vote for him.

According to the paper, Obama has to perform a delicate balancing act, remaining his own man while wooing Mrs Clinton''s supporters - particularly the wealthiest ones - and persuading his own donors to help pay off the more than 20 million dollars in campaign debt that the New York senator has saddled herself with.

All the signs, however, are that Obama is inclined to plump for someone else.

Governor Kathleen Sebelius of Kansas, Senator Clair McCaskill of Missouri and Senator Joe Biden of Deleware, Senator Jack Reed of Rhode Island, and Senator Evan Bayh of Indiana are thought to be on Obama''s running mate short-list.

Bayh could emerge as the ideal compromise candidate. As a former governor, he has executive experience outside Washington while as a member of the Senate Armed Services Committee he has solid foreign policy credentials.

He hails from a Mid-Western state and could thus appeal to the white working-class voters Obama failed to win over against Clinton and choosing a members of the former First Lady''s camp could help placate her backers. (ANI)