The Republican presidential nomination contest was energized last week by Representative Michelle Bachmann’s victory in the Ames straw poll, combined with Texas Governor Rick Perry’s announcement that he would be joining the race. The unofficial starting whistle for the 2012 presidential election has now been blown.Recent events aside, the most striking feature of the Republican race (which currently has at least a dozen official entrants) has so far been the distinct lack of excitement surrounding it. With the US economy still weak, and Barack Obama thus vulnerable, this has puzzled many.Following Bachmann’s victory and Perry’s entrance, the good news for the Republicans is that the contest will now heat up. However, the race’s outcome has become even more uncertain, as both of these Tea Party favorites will now challenge the early leader: former Massachusetts governor Mitt Romney, a relatively moderate conservative.A crucial factor that will help determine whether Republicans win back the White House in November 2012 is whether the party will decisively unite around a credible candidate. A model here would be the 2000 nomination cycle, when George W. Bush emerged strongly in late 1999 and early 2000 from a wide field of candidates, well before the official nominating season began.However, unlike 2000, the current Republican race may prove unusually turbulent, divisive and perhaps drawn out. Uncertainty may only be intensified by the Tea Party’s growing influence in Republican ranks.Of course, US presidential nomination contests always have unexpected twists. What distinguished the 2004 and 2008 cycles, however, was the relative difficulty of predicting the eventual Democratic and Republican nominees (with the exception of Bush in 2004, whose Republican re-nomination was uncontested). In both 2004 and 2008, the Democratic Party’s early front-runner – defined as the candidate leading in national polls of party identifiers on the eve of the Iowa caucuses and raising more campaign finances than any other candidate in the 12 months before election year (Howard Dean and Hillary Clinton respectively) – was ultimately beaten by initially less-favored candidates (John Kerry and Obama respectively).In the 2008 race for the Republican contest, John McCain emerged as the nominee, despite the fact that other candidates (Rudolph Giuliani and Romney) had greater national poll strength and fundraising prowess before the nominating season began.There appears to be no common factor accounting for the success of Kerry, Obama and McCain. For instance, much of Vietnam veteran Kerry’s surge was fueled by “late” concerns among Democrats that Dean’s lack of national security credentials made him unelectable against Bush during the “war on terror.”By contrast, Obama’s success was driven, in significant part, by a factor that was genuinely new in the post-2000 cycles: the fundraising and campaigning potential of the Internet. This was used by his campaign to overcome Clinton’s organization.Far from being the norm, the collapse of the early front-runners in 2004 and 2008 was most unusual in the past three decades of presidential races. Indeed, from 1980 to 2000, the eventual nominee in eight of the 10 contested Democratic and Republican nomination races was the preprimary front-runner.This was true of Jimmy Carter, the Democratic nominee in 1980; Walter Mondale, the Democratic candidate in 1984; George H. W. Bush, the Republican nominee in 1988 and 1992; Bill Clinton, the Democratic candidate in 1992; Bob Dole, the Republican nominee in 1996; Al Gore, the Democratic nominee in 2000; and George W. Bush, the Republican nominee in 2000.In both of the partial exceptions to this pattern, the eventual presidential nominee led the rest of the field on one of the two measures: In the race for the 1980 Republican presidential nomination, Ronald Reagan (who ultimately won the contest) led national polls of party identifiers, although John Connally was the leading fundraiser. In the battle for the 1988 Democratic nomination, Michael Dukakis (who eventually won the race) raised the most, but was behind in national polls on the eve of the Iowa caucus to Gary Hart.For Obama, a divisive, drawn-out Republican contest would undoubtedly aid his reelection chances. With his job approval ratings remaining below 50 percent, it will be an uphill struggle to recapture the spirit of his hugely successful 2008 campaign.Indeed, even if he becomes the first presidential candidate in US history to raise $1 billion in campaign finances, thus potentially giving him an edge over his eventual Republican rival, Obama’s prospects in 2012 may now rest heavily on a factor that remains largely out of his hands: whether the US economy can avoid a “double-dip recession.”The writer is an associate partner at ReputationInc, and was formerly US editor at Oxford Analytica and a special adviser in UK prime minister Tony Blair’s government.