Votes for Meg Whitman and Barack Obama

Tonight, all eyes are on Obama and McCain, in their final Presidential debate. If McCain continues to lose in the polls, it’s all the more likely that one of his key advisors — and one of Fortune’s former No. 1 Most Powerful Women — will set her sights on another race: for California Governor. Former eBay CEO Meg Whitman, who is co-chair of the McCain Presidential campaign, hasn’t decided whether to run in the 2010 gubernatorial contest, but signs point to her doing so. She has retained McCain strategist Steve Schmidt and his firm, Mercury Public Affairs, as an advisor.

Granted, eBay has big growth problems today (the company will report quarterly earnings after the market close today), but Whitman will run on her impressive record of building an organization from 30 people to 15,000 when she handed over the CEO reins to John Donahoe this past March. Revenues rose from $4 million to $7.7 billion during her 10-year tenure. If she runs for governor, her competitors for the Republican nomination will likely include California Insurance Commissioner Steve Poizner and maybe former Hewlett-Packard CEO Carly Fiorina — a McCain adviser who, coincidentally, topped the Fortune MPWomen list for six straight years before she got ousted from HP and Whitman replaced her as No. 1 on the list.

While Fiorina has considered running for governor, she is less likely to following last month’s flap over her remark that Sarah Palin doesn’t have the experience to run a major company like Hewlett Packard. (The flap was ridiculous and unfair; as Fiorina told the interviewer, “That’s not what she’s running for.” The fact is, neither McCain, Obama nor any other politician has the experience to run Hewlett-Packard — and this doesn’t diminish their ability to lead the nation.)

If Whitman decides to enter the gubernatorial race and wins the Republican nod, she could be competing with any of these Democrats who have signalled interest in running: California Attorney General (and former Governor) Jerry Brown, Los Angeles Mayor Antonio Villaraigosa, San Francisco mayor Gavin Newsom, Lieutanant Governor John Garamendi, and former Controller Steve Westly, who failed to win the Democratic nomination two years ago. Brown is viewed as the favorite among the Democrats. But how interesting it would be if it were Whitman vs. Westly. Westly, one of eBay’s first executives, once worked for Whitman, heading marketing and business development. Even more intriguing: If Senator Dianne Feinstein runs — as she is rumored to do every four years — California could have an all-female contest. Feinstein’s age is her disadvantage. She’s 75. Whitman is 52.

Here’s one positive sign for Whitman: Last month, we asked 126 participants of Fortune’s Most Powerful Women Summit, “Who is more likely to become the next Governor of California? Carly Fiorina or Meg Whitman? Twenty-six percent said Fiorina. Sixty-eight percent said Whitman. (Six percent said they don’t know.)

As for the bigger race — for the Presidency — 57% of the MPWomen Summit participants predicted that Obama will win. The exact same percentage said they want Obama to win. McCain’s MPWomen votes weren’t pretty. Only 39% predicted that McCain will win the Presidency. Even fewer, 29%, said they’d likely vote for him.

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