GOP wasn't expecting this challenge

Citing a legislative investigation into Palin's firing of the state public safety commissioner -- a matter allegedly linked to a family dispute -- Cook suggested: "She can't take on a whole lot more water." On Monday, it was disclosed that the state had hired a private attorney to represent Palin in the legislative probe and also that her husband had been arrested for drunken driving more than two decades ago.

With scores of reporters descending on Alaska to comb through Palin's background, McCain aides said the campaign had dispatched a team of lawyers and other campaign operatives to the state. The aides denied that McCain was vetting Palin again.

The latest development raises questions about the thoroughness of the process leading up to Palin's selection. A GOP source with close ties to the campaign said that McCain aides "vetted her through Google and clipping services."

"They didn't send lawyers there or talk to people who knew her there," said the source, who did not want to be identified discussing the campaign's inside moves.

But Palin spokeswoman Maria Comella said more than two dozen McCain aides reviewed public records and legal documents, her credit history, news accounts, speeches, financial records and any formal complaints against her. Palin completed a 40-page questionnaire and was interviewed for three to four hours by Arthur B. Culvahouse Jr., a longtime Washington attorney, and spoke at length with McCain's top advisors.

In the interview with Culvahouse, Palin disclosed her daughter's pregnancy and her husband's DUI, Comella said.

Schmidt told reporters that the campaign issued the statement on Bristol's pregnancy to rebut Internet rumors that the governor's 4-month-old baby, Trig, is in fact Bristol's child.

The father of Bristol's baby was identified in the statement as Levi, but the campaign said it was not disclosing his full name or age or how he and Bristol know each other.

"We had hoped this could be an issue that was private -- that the family could deal with this issue privately," Schmidt told reporters who swarmed him at the convention soon after the statement was issued. "It used to be that a lot of those smears and the crap on the Internet stayed out of the newsrooms of serious journalists. That's not the case anymore."

Although the campaign declined to release the father's full name, residents of the Palins' hometown of Wasilla, Alaska, seemed familiar with the couple. They identified the father as a fellow high school senior and a prominent player on the school hockey team.