Former Alaska Gov. Sarah Palin announced she is not running for the 2012 Republican presidential nomination, drawing a line under months of speculation.

"After much prayer and serious consideration, I have decided that I will not be seeking the 2012 GOP nomination for president of the United States," she said Wednesday in a letter to supporters.

"(M)y decision is based upon a review of what common-sense conservatives and independents have accomplished," Palin wrote. "I believe that at this time I can be more effective in a decisive role to help elect other true public servants to office - from the nation's governors to congressional seats and the presidency."

"We need to continue to actively and aggressively help those who will stop the 'fundamental transformation' of our nation and instead seek the restoration of our greatness, our goodness and our constitutional republic based on the rule of law," the letter continued.

Palin became a national figure in 2008 when Republican presidential candidate John McCain chose her as his running mate.

In July 2009, she stepped down as Alaska governor midway through her term and became the unofficial standard-bearer of the Tea Party movement.

Palin's announcement came a day after New Jersey Gov. Chris Christie shut the door on running for the 2012 Republican nomination.

With Christie and Palin out of the picture, the race appears to be between Texas Gov. Rick Perry and former Massachusetts Gov. Mitt Romney.