ST. PAUL, Minn. — Governor Palin’s husband, Todd, twice registered as a member of the Alaskan Independence Party, a fierce states’ rights group that wants to turn all federal lands in Alaska back to the state. Ms. Palin herself was never a member of the party, according to state officials.

Questions about a third-party link to senator McCain’s new running mate emerged today as the latest issue facing the McCain campaign in the midst of the Republican National Convention.

Questions had swirled about Ms. Palin’s affiliation with the Independence Party and with a former presidential candidate, Pat Buchanan. Voter registration records and past news reports, however, show Ms. Palin never registered as a member of the Independence Party, and backed Steve Forbes’ presidential campaign in 2000, not Mr. Buchanan.

“Supporters of Barack Obama are engaged in an unfortunate and nasty smear campaign,” a McCain spokesman, Brian Rogers, said, specifically citing issues related to Ms. Palin’s politics.

The director of the Alaska Division of Elections, Gail Fenumiai, said Mr. Palin twice registered under the Alaskan Independence Party — in 1995 and 2000. Some members of the party have advocated secession from America, though that is not a goal listed in the party’s platform.

Voter registration records show Ms. Palin registered in May 1982 as a member of the Republican Party and has not changed her affiliation. Mr. Palin has been registered undeclared since 2002, Ms. Fenumiai said.

Ms. Palin did address the Alaskan Independence Party’s state convention by video earlier this year, welcoming the party to Fairbanks.

“Your party plays an important role in our state’s politics,” she said in the video, which is posted on the party’s Web site. “I’ve always said that competition is so good, and that applies to political parties as well.”

An Obama spokesman, Bill Burton, objected to Mr. Rogers’s accusation of a smear. He pointed to comments by the chairman of the AIP, Lynette Clark, who told ABC News that Ms. Palin and her husband belonged to the party in 1994.

Obama advisers and surrogates have linked Ms. Palin to Mr. Buchanan. An Associated Press story from Alaska, dated July 17, 1999, stated that Ms. Palin, then the mayor of the small town of Wasilla, was wearing a Buchanan button during a Buchanan visit to Alaska.

But in a letter to the Anchorage Daily News a week later, Ms. Palin wrote: “When presidential candidates visit our community, I am always happy to meet them. I’ll even put on their button when handed one as a polite gesture of respect. … The article may have left your readers with the perception that I am endorsing this candidate, as opposed to welcoming his visit to Wasilla.”

A week after that, the Associated Press reported that Ms. Palin would serve as a co-chair of Mr. Forbes’s campaign.

Still, the Miami Herald this week quoted an e-mail from an Obama Florida spokesman, Mark Bubriski, that stated: “Palin was a supporter of Pat Buchanan, a right-winger or as many Jews call him: a Nazi sympathizer.”