Factbox: Possible Republican White House candidates in 2012

(Reuters) - Soon after the dust settles on the midterm elections, the U.S. political focus will shift to the 2012 battle for the White House and a growing stable of Republicans who might like to take on President Barack Obama.

Following is a list of Republican presidential wannabes, many of whom have already built robust fund-raising operations and paid repeated visits to the early battleground states of Iowa and New Hampshire.

MITT ROMNEY

A leading candidate in the 2008 presidential race, former Massachusetts Governor Mitt Romney has carefully positioned himself for a return to White House politics with repeated visits to Iowa and New Hampshire, as well as a book tour. Known for his good looks and personal charm, Romney also joins Newt Gingrich, Sarah Palin and Tim Pawlenty as a leading Republican fund-raiser. His Free and Strong America political action committee has raised more than $7.7 million in the current election cycle. But he continues to be followed by claims of flip-flopping, a charge that detracted from his 2008 presidential bid. A recent example came earlier this year when Romney assailed Obama's health care reform package as an abuse of power. The remark quickly drew comparisons between the Obama legislation and state reforms implemented in Massachusetts during his governorship.

TIM PAWLENTY

Minnesota Governor Tim Pawlenty first emerged as a potential contender in White House election politics in 2008, amid speculation that he could become Republican John McCain's running mate. Though the mantle went to Palin, Pawlenty is now viewed as a leading GOP presidential hopeful. He has built up a political presence in both Iowa and New Hampshire by making repeated visits. His Freedom First fund-raising body has collected more than $3 million in the current election cycle. As a popular Republican governor in a traditionally Democratic state, Pawlenty eliminated a $4.3 billion budget deficit without raising taxes and has been a staunch voice against abortion and stem cell research.

SARAH PALIN

Former Alaska Governor Sarah Palin has used lucrative TV, book and speaker deals to emerge as one of her party's biggest stars since becoming the 2008 Republican vice presidential nominee. She is a leading voice in the fiscally conservative Tea Party movement and has enhanced her influence this year by campaigning for Republican congressional candidates across the country. Those activities and her success at fund-raising are driving speculation of a possible Palin White House run in 2012. Since the 2010 election cycle began, her political action committee has collected about $5 million.

MIKE HUCKABEE

Distinguishing himself as a conservative who is "not angry," the former Arkansas governor used a mixture of anti-abortion, anti-gay politics and regular-guy charm to win the 2008 Republican Iowa caucus against candidates with bigger names. A former Baptist minister with strong ties to the Christian Right, Huckabee continues to poll strongly in Iowa and has been seen as a potential presidential front-runner in 2012. But he is also dogged by controversy for granting clemency to Arkansas criminals, including a felon who later allegedly murdered four Washington state policemen and died in a gun battle with a Seattle officer.

NEWT GINGRICH

The former speaker of the U.S. House of Representatives was the main architect of the 1994 Republican midterm election victory and author of the Contract with America political manifesto. But the Georgia Republican ended his 20-year congressional career after his leadership was marred by big losses in the 1998 midterm elections. Gingrich remains a leading conservative figure, political pundit and accomplished fund-raiser whose political advocacy group has outstripped his Republican rivals by collecting more than $20 million during the 2010 election cycle.

HALEY BARBOUR

Little known outside political circles, Mississippi Governor Haley Barbour is a powerful conservative leader and one of the country's most experienced politicians. Barbour is credited with helping to engineer the Republican takeover of Congress in 1994, as Republican National Committee chairman. As governor, the former tobacco lobbyist worked with a largely Democratic legislature to erase a state fiscal deficit of more than $700 million by cutting spending and avoiding higher taxes. His current leadership of the Republican Governors Association is also seen as a driving force behind expected GOP gains in November's gubernatorial races.

MITCH DANIELS

Indiana Governor Daniels has not visited either Iowa or New Hampshire. But U.S. media speculate that he could become a strong Republican candidate for the White House. A director of the White House Office of Management and Budget under former President George W. Bush, Daniels has a proven track record of reducing the size of government, balancing the budget, cutting taxes and creating jobs. But he has been attacked for breaking with fiscal conservative ideals on taxation. Grover Norquist of Americans for Tax Reform recently charged that Daniels disqualified himself by going "beyond the pale" with a call for a flat income tax and a value added tax to discourage consumption and encourage savings and investment.

OTHERS

Others seen as testing the presidential waters include Senator Scott Brown of Massachusetts, Senator Jim DeMint of South Carolina, South Dakota Senator John Thune, New Jersey Governor Chris Christie, Louisiana Governor Bobby Jindal, Representative Mike Pence of Indiana, Representative Paul Ryan of Wisconsin and Representative Ron Paul of Texas -- a former candidate for the Republican nomination.

The fund-raising data on the potential candidates comes from the Center for Responsive Politics, a nonpartisan group that tracks the role of money in U.S. elections.

(Reporting by David Morgan and Steve Holland in Washington, Ellen Wulfhorst in New Hampshire; Editing by Anthony Boadle)