* Republican faces a defining moment in Tampa
* Largely writing Thursday's speech himself
* A focus on Romney's biography and likability
By Steve Holland
TAMPA, Fla. Aug 27 (Reuters) - For the most important speech of his political career, Mitt Romney has turned to those he trusts the most: himself, his wife, Ann, and a top aide.
The speech that the Republican presidential candidate will deliver Thursday night, in the coda to his party's convention and seen by millions on national television, is being written largely by Romney himself.
"The governor wants to make sure the words are right and that they are his," said a senior aide.
In addition to Romney's wife, senior strategist Stuart Stevens will be helping with the speech.
In what aides characterize will be a speech of roughly 40 minutes, Romney will have a crucial opportunity to raise his likability factor among voters and refute the Democrats' attempts to paint him as a job-killing former private equity executive who is out of touch with middle America.
His other main goals are to define himself to U.S. voters who don't know him well and offer a vision for how he would rebuild the U.S. economy. There will also be criticism of the leadership of his rival, Democratic President Barack Obama.
Polls indicate that Romney is not as well known or as well liked as the Democratic incumbent. Romney aides say they - and Romney himself - recognize that the former Massachusetts governor has work to do in making voters more comfortable with him as an alternative to Obama in the Nov. 6 election.
The Romneys' effort to do that begins Tuesday night, when Ann Romney will deliver her own speech to the convention delegates.
With the start of the Republican convention delayed in deference to Tropical Storm Isaac, the Romneys have spent the past two days holed up in their Wolfeboro, New Hampshire, vacation home, working on their convention speeches. They emerged twice to rehearse at Brewster Academy, a nearby boarding school.
"I like my speech. I really like Ann's speech," Romney told reporters after a practice session. "We're looking forward to a great convention."
A potential theme of one or both of the speeches might have been revealed late Sunday, when a Reuters photographer took a photo of Ann Romney's legal pad as she carried it out of the school.
The photo showed a handwritten biblical verse from Deuteronomy 15:11: "Thou shalt open thine hand wide unto thy brother, to thy poor and to thy needy."
Such a message could be apt for a candidate who is looking to counter the image Obama and his allies have built of Romney over the summer: that of a distant, uncaring executive whose business helped send U.S. jobs to China.
A DIFFERENT APPROACH
Romney's approach to his speech appears to differ from that of George H.W. Bush, who during the 1988 campaign faced similar questions about his ability to connect with voters in a personal way.
Bush enlisted the help of Peggy Noonan, the author of some of President Ronald Reagan's most memorable speeches.
In the convention speech Noonan helped to write for Bush, he said he would seek a "kinder, gentler nation" and called volunteers and community organizations "a thousand points of light" that helped to improve society.
The speech also included the "read my lips, no new taxes" phrase that would be Bush's undoing in his loss to Democrat Bill Clinton four years later.
In taking on much of the speech-writing task himself, Romney has gotten advice from Stevens, a longtime political operative who frequently is on the campaign trail with Romney.
Stevens has a low-key way of dealing with the candidate, advisers say.
"They are in sync and have complete confidence in each other," one adviser said.
HURDLES TO OVERCOME
Romney gets high marks in opinion polls on how he would handle the weak economy, but faces a particular challenge in improving his likability among voters.
An ABC News/Washington Post poll published on Tuesday said Obama was seen as more likable than Romney by a wide margin, 61 percent to 27 percent.
Romney told Politico in an interview published on Monday that he was not going to put on a charade to win voters.
"I know there are some people who do a very good job acting and pretend they're something they're not," Romney said. "You get what you see. I am who I am."
Ed Gillespie, a senior Romney adviser, said the speech will be a critical moment for Romney at a convention where many speakers will provide testimonials about his life and career as an executive at Bain Capital, leader of the Salt Lake City Olympics and governor of Massachusetts.
"I think it's important," Gillespie said. "It's Thursday night and it's a moment when a lot of people will be paying attention and watching, tens of millions of Americans, many of whom have not really been paying close attention."
Although Romney has obvious hurdles to overcome - besides his likability issues, Romney trails Obama among women and Hispanics, for example - the Republican's advisers say they have reason to be optimistic about the fall campaign.
"People know who President Obama is. They don't yet who Governor Romney is. But the polls are tied. We think that's a positive sign for us," said a Romney campaign spokesman, Ryan Williams.
Ari Fleischer, a former White House press secretary who is a Republican analyst, said Romney - who can appear robotic and distant on the campaign trail - "needs to establish ... a positive, emotional connection" with viewers.
"They know his ideological differences with Obama," Fleischer said. "They're not sure who he is yet. He needs to show that people can like him."
The overall convention will provide "nice background music," but Romney must hit the right notes, Fleischer said.
"He needs to lay out what President Obama has done wrong, what he would do right. And he has to be affable. A little humor would help," Fleischer said. "That's how you connect. He can't be wonky, boring, too policy oriented. He needs to be human, personal, warm." (Additional reporting by Sam Youngman in Wolfeboro, New Hampshire; Editing by Leslie Adler)