WASILLA, Alaska — Alaska Gov. Sarah Palin abruptly announced Friday she will resign from office at the end of the month, a shocking move that rattled the Republican Party but left open the possibility she would run for the White House in 2012.

Palin, 45, and her staff kept her plans shrouded in mystery, and whether the controversial hockey mom would quietly return to private life or begin laying the foundation for a presidential bid remained unclear.

David Murrow, Palin’s spokesman, said the governor didn’t say anything to him about this being her “political finale.” He said he interpreted Palin’s comment about working outside government as reflecting her current job only.

“She’s looking forward to serving the public outside the governor’s chair,” he said.

And Pam Pryor, a spokeswoman for Palin’s political action committee Sarah- PAC, said the group continues to accept donations on its Web site, with an uptick in funds after Palin’s announcement.

In a hastily arranged news conference at her home in Wasilla, an Anchorage suburb, Palin said she formally will step down July 26, and Lt.Gov. Sean Parnell will be inaugurated at the governor’s picnic in Fairbanks. She said she had decided against running for reelection as Alaska’s governor and believed it was best to leave office even though two years remain in her term.

“Many just accept that lame duck status, and they hit that road. They draw a paycheck. They kind of milk it. And I’m not going to put Alaskans through that,” she said.

Last year’s vice presidential nominee was considered a likely presidential contender in 2012 and had proved formidable among the party’s base. But the last week brought a highly critical piece in Vanity Fair magazine, with unnamed campaign aides questioning if Palin was ever really prepared for the presidency.

The backbiting continued through the week, with follow-up articles recounting the nasty infighting that plagued her failed bid. Her advisers sniped with other Republicans, underscoring the deeply divided GOP looking for its next standard bearer.

Meghan Stapleton, Palin’s personal spokeswoman, shot down speculation that ranged wildly from Palin dropping out of politics altogether to eyeing runs against Rep. Don Young and Sen. Lisa Murkowski, two other Alaska Republicans. Palin’s comment about serving outside government refers to the present, she said.

Stapleton, however, said it’s too early to say whether Palin would seek the presidency. In the meantime, the governor will continue to work “toward affecting positive change as a citizen without a title right now,” she said.

“Her vision is what’s best for Alaska, which translates into what’s best for America,” Stapleton said.

Palin’s resignation, timed on the eve of the July Fourth holiday when many Americans had already begun a three-day weekend, seemed designed to avoid publicity. She alluded to how she could help change the country and help military members — code that she didn’t think her time on the national stage was over.

Jerry McBeath, a veteran political science professor at the University of Alaska Fairbanks, called the pending resignation a “smart move,” both for Palin and the state.

“Alaska is an isolated stage from which to operate if you want to figure in American national politics. I don’t know what she has in mind. Some TV show or some national radio show. There are opportunities for her, I’m sure.”

But political analyst Larry Sabato, in Charlottesville, Va., said Palin’s announcement left many confused.

“It’s absolutely bizarre, and I think it eliminates her from serious consideration for the presidency in 2012,” he said.

Palin said her family weighed heavily in her decision.

“I polled the most important people in my life, my kids, where the count was unanimous,” she said. “Well, in response to asking, ‘Hey, you want me to make a positive difference and fight for all our children’s future from outside the governor’s office?’ It was four yeses and one ‘Hell, yeah!’ And the ‘Hell, yeah’ sealed it.”

Palin’s decision not to seek re-election was a familiar one for a potential presidential candidate. Former Massachusetts Gov. Mitt Romney chose not to seek another term as he geared up for an unsuccessful 2008 presidential bid. Minnesota Gov. Tim Pawlenty has announced he won’t seek another term, giving him plenty of free time ahead of a potential 2012 bid.

Palin emerged from relative obscurity nearly a year ago when she was tapped by Sen. John McCain, the Republican presidential candidate, as his running mate.

In the presidential race, Palin became the butt of talk-show jokes and Democratic criticism after news broke that the Republican Party had spent $150,000 or more on a designer wardrobe, accessories and hair and makeup services for her. The high-end spending spree contrasted with the down-to-earth image she sought to craft for herself and became an unwelcome issue for the McCain campaign.

She didn’t leave the limelight once McCain lost his bid for the presidency. She recently led a public spat with “Late Show” host David Letterman over a joke he made about one of her daughters being “knocked up” by New York Yankees baseball player Alex Rodriguez during the governor’s recent visit to New York. Palin’s 18-year-old daughter, Bristol, is an unwed mother. Letterman later apologized for the joke.

Palin was first elected in 2006 on a populist platform, but her popularity has waned.