Former Gov. Sarah Palin said Wednesday she will not be running for president in 2012.
Palin, the Republican vice presidential nominee in 2008, made the announcement on the national Mark Levin radio talk show, saying her family's wishes were the main factor in her decision but also that she felt she could have the most impact by being "unshackled" to support candidates she liked.
"I am very thankful that included in a list of supporters in my life are my family members," Palin told the conservative talk show host. "They do support this decision. They came first, the consideration of what a candidacy does to or for a family. That weighed heavily."
Palin promised to still play a role in national politics. She said she expected to be active in trying to defeat President Barack Obama and to support like-minded candidates running for Congress and in races for governor across the country.
"I believe not being a candidate you're really unshackled and you're allowed to be even more active," Palin told the radio host.
Palin's written announcement, later emailed to supporters of her political action committee and posted on her Facebook page, said she would not seek the Republican nomination, and she also told Levin she wouldn't run as a third party candidate.
"I would assume a third party would just guarantee Obama's re-election," Palin said.
Palin thanked her supporters in the tea party movement, people she called "Americans who are independent and patriotic and know our republic is worth defending."
Her announcement comes a day after Republican New Jersey Gov. Chris Christie said he, too would not be running for president.
Alaska Republican Sen. Lisa Murkowski, who has been critical of Palin, said the decision not to run came as no surprise.
"I had come to the decision some time ago that she would likely not run. There were certainly mixed signals that were out there but it just didn't seem to me that if she was serious about it that she would have held out this long," Murkowski said.
Palin never made any real moves toward establishing a political campaign, focusing on her role as a highly paid speaker and commentator on Fox News. But there has been months of intense media speculation about whether she might run and her core group of die-hard supporters had continued to insist there was still time and that she had a chance to win.
HARD-CORE FANS SURPRISED
Palin's announcement appeared to come as a surprise to some of her most ardent fans. Commenters on her Facebook page initially questioned if it was real.
The Conservatives4Palin website, which on Wednesday was still running columns touting her chances to win to the presidency, didn't post the news she wasn't running until well after it was announced.
Conservatives4Palin followed it with a column in which regular contributor Nicole Coulter wrote "my first reaction was disbelief ... and then I felt numb.
"I've had about an hour to process everything, and I just want to tell everyone that we must keep up the good fight," she wrote.
Palin's political action committee sent an email to supporters Wednesday afternoon saying "after much prayer and serious consideration" she would not be running for president.
Palin also sent out a Twitter message that contained a link to a video produced by her political action committee, SarahPAC.
The video, entitled "Moving Forward," featured rousing music and included shots of a grizzly bear, the Statue of Liberty and Palin surrounded by crowds. "You don't need an office or a title to make a difference," Palin declares.
Gov. Rick Perry of Texas, whose presidential campaign might have battled against Palin for many of the same supporters had she run, released a statement praising her. "Sarah Palin is a good friend, a great American and a true patriot," Perry said. "I respect her decision and know she will continue to be a strong voice for conservative values and needed change in Washington."
Arizona Republican Sen. John McCain, who brought Palin to national prominence by picking her as his presidential running mate in 2008, said on Twitter, "I am confident she'll continue to play an important role in our party and for our nation."
Palin had been relatively quiet in recent weeks, after a Labor Day weekend visit to Iowa that drew supporters from around the nation and a June bus tour to historical landmarks around the country. She went on Greta Van Susteren's Fox News program in late September, raising the suggesting that a title, even that of president, might "shackle" her from getting her message out.
Palin's email to supporters Wednesday is datelined Wasilla, but she has largely been out of sight in Alaska since resigning a little more than halfway through her term as governor on July 26, 2009. Palin plays no role in the state's politics and sightings of her in her home state are few and far between. There's been no visible Alaska movement to get her to run.
Her poll numbers in Alaska have not been good, and a late June poll suggested Obama would beat Palin among Alaskans in a head-to-head race.
Her national poll numbers have also generally not been encouraging, although a McClatchy-Marist poll from last month found that Palin appeared to gain some ground nationally. The survey, taken Sept. 13-14, found that after trailing Obama by more than 20 percentage points in polls all year, she was trailing him by just 5 points, 49-44 percent.
But that didn't mean Republicans thought she could win. The same poll found that by a margin of 72 percent to 24 percent, Republicans and Republican-leaning independents did not want Palin to run for president. Even among tea party supporters, 68 percent did not want her to run.
Palin's Wednesday letter focused on what she considers to be her ongoing role influencing national politics, saying that she "will continue driving the discussion for freedom and free markets."
Reporter Erika Bolstad contributed from Washington, D.C.