Former Minnesota Governor and Republican presidential hopeful Tim Pawlenty speaks to students

AFP

Republicans aiming to topple President Barack Obama in 2012 will tackle each other Monday with their first big televised debate and a chance to grab national attention, reports AFP.

Seven potential or declared White House candidates will debate in Manchester, New Hampshire, where Republican hopefuls are already campaigning eight months ahead of the first in a gruelling series of state primaries.

With former Massachusetts governor, Mitt Romney the firm frontrunner for the party nomination, rivals including Tea Party favourite Congresswoman Michele Bachmann and conservative former Minnesota governor Tim Pawlenty are expected to come out fighting.

The stakes are high, since candidates not only want national recognition, but need to impress voters in tiny New Hampshire, where a good or poor showing in February's primary can crucially influence momentum heading into similar contests in other, much bigger states.

Republicans believe that Obama is vulnerable towards the end of his first term over the nation's still anaemic recovery from recession and persistent high unemployment.

But in an election season where the Republican Party faces internal tensions between moderates and the Tea Party wing, the nomination race is proving unpredictable.

One of the best known figures in Monday's debate, former speaker Newt Gingrich, saw his campaign threaten to unravel last week when much of his staff resigned.

With so much volatility, some predict the relatively unknown Herman Cain -- the only African American candidate for the Republican nomination -- could snatch a major boost from the debate, which will air live on CNN.

The pizza entrepreneur has used forceful speaking skills to come from nowhere against the more established politicians and attract an enthusiastic and growing following. The latest Gallup poll, released Sunday, puts him a surprise third in the Republican field.

Other challengers at the debate include libertarian Texan Congressman Ron Paul and socially conservative former Pennsylvania senator Rick Santorum, both of them likely to contribute to a heated discussion.

During a campaign stop Sunday in a remote corner of New Hampshire, Pawlenty promised Monday's clash would help bring definition to the Republican pool.

"We're going to be talking about who we are," he said. "There's going to be differences between Republican candidates."

Apart from hammering Obama, one thing most of the candidates might agree on is ganging up against Romney who in the new Gallup poll leads with 24 percent of Republican support.

Although the ex-governor is seen as the most heavyweight challenger, with the experience of a failed 2008 bid under his belt, critics question his charisma.