WASHINGTON (Reuters) - Sarah Palin faces a dilemma.
The conservative firebrand could use her electrifying, combative personality to leap into the race to determine the Republican nominee to run for U.S. president in 2012.
Palin is the only big-name Republican left who could launch a run this late and has said she will make the decision by the end of this month.
But by doing so, she would risk a new round of unflattering publicity -- the kind of negative focus on her and her family that dogged her vice presidential run in 2008 and left her embittered by the experience.
A taste of that has already come with an unflattering new book by a veteran political writer that makes unsubstantiated allegations about Palin, a former Alaska governor.
While adverse publicity may generate sympathy among her supporters, it could damage her image among the broader electorate, raising the question of whether she could be electable in a run against Democratic President Barack Obama in November 2012 or against anyone else in 2016.
There are signs she will not jump into the race, including a clue she gave in a Fox News interview this week, when she said after a Republican debate that she enjoyed the influence she was having without being a candidate.
Palin, 48, said she is "getting a kick out of getting out there, giving a speech, making some statements about things that must be discussed and then the very next day watching some of the candidates get out there and discuss what it was that we just talked about."
Plus, she has little in the way of organization that could form the basis of a campaign in the early voting states like Iowa and New Hampshire. Most of the top organizing talent has been hired by other candidates and Republicans are only four months away from the start of voting in primary elections.
"She's a rock star," said Steve Duprey, a former New Hampshire Republican Party chairman and adviser to Senator John McCain's 2008 presidential campaign when Palin was his running mate.
"I think if she got in she'd be a very potent force. She has a large following and she inspires people," Duprey said. "But from a logistical standpoint I think it would be extremely difficult in the early primary states for her to put together an effective organization."
A book by author Joe McGinniss, "The Rogue: Searching for the Real Sarah Palin," is due to be released next week and continues the drumbeat of allegations against her.
It alleges that as an unmarried, 23-year-old sports reporter, she had a one-night stand with a future professional basketball player and later had an affair with a business associate of her husband Todd.
Todd Palin issued a withering statement about McGinniss and his book, saying he has a "creepy obsession with my wife."
"His book is full of disgusting lies, innuendo, and smears. Even The New York Times called this book 'dated, petty,' and that it 'chases caustic, unsubstantiated gossip,'" he said.
The business associate, Brad Hanson, called the charge involving him a "complete and outright lie."
"Todd and Sarah Palin have been good friends for many years and in fact we still own property together," he said.
David Yepsen, director of the Paul Simon Public Policy Institute at Southern Illinois University, said the allegations may make her a sympathetic figure among supporters but will not help her to convince other voters she is presidential timber.
"If she doesn't look presidential, even if there's really nothing new in the book, there's just a few more days of buzz about her and her personal life and all the issues," he said.
"It's just going to reinforce negative opinions of her. It's just not helpful."
Still, the negative portrayals of the self-styled "mama grizzly" could steel her for a presidential run.
She has always been willing to take on what she derisively calls the "old boys club" of Republican politics and never shies away from a fight.
And while the criticism of her remains -- that she does not seem to have conducted a serious study of all the issues that a president faces -- she retains a strong following among Tea Party conservatives as a politician who knows how to generate enthusiasm with her folksy, "you betcha" manner.
"All I can tell you is she has come out to Tea Party Express rallies a half dozen times or more and there really is no one who electrifies the crowd the way that Sarah Palin does," said Levi Russell, the group's spokesman. "Without a doubt she's the most exciting figure in politics."
(Editing by John O'Callaghan)