Are Republicans planning to choose the party "heir apparent" as their 2012 presidential candidiate, as they have in so many years past, regardless of his popularity or electability? Or faced with an historic Democratic opponent like Barack Obama, and under pressure from Tea Party insurgents, will the GOP finally decide to "go rogue"?

That's the big question facing party leaders and voters as the Republican field narrows but continues to fragment, with different candidates starting to secure footholds in different states and with potentially competing voter groups.

Former Massachusetts Governor Mitt Romney, who finished second to John McCain in 2008, is still widely viewed as the presumptive GOP frontrunner. He has the largest war chest, the best field organisation, and the most presidential campaign experience of any Republican candidate currently running or planning a bid. But persistent questions about his candidacy – fuelled by his embrace of "RomneyCare", his devout Mormonism and his persistent flip-flopping on social issues – remain.

And if anything, Romney's Memorial Day weekend visit to bellwether Iowa – scene of the first-in-the-nation Iowa caucuses, which Romney unexpectedly lost in 2008, crippling his campaign that year – have only confirmed those doubts anew. Romney's first stop in Iowa was in Des Moines, where he gave a largely boilerplate economic speech to the Greater Des Moines business partnership. The event led to contentious questioning about his actual commitment to the state, and the event was interrupted – and abruptly ended – by a fire alarm, apparently triggered by burning popcorn. Not an auspicious sign.

Romney also took time to announce his new state campaign staff, headed by Sarah Craig, who oversaw his large Iowa campaign operation in 2008. This time Craig will oversee what amounts to a shoestring operation – a clear sign of how little Romney's actually planning to invest in the state.

That Romney even made this visit to Iowa was something of a surprise. As recently as March, it was rumoured that Romney was planning to skip the state entirely in order to consolidate his already-impressive campaign operation – and huge polling lead – in New Hampshire and Nevada, the two states that have emerged as the bulwark of his "frontloaded" campaign strategy.

But a combination of factors, above all, Mike Huckabee's recent withdrawal from the race, convinced Romney that he needed to "show the flag" in Iowa, or risk alienating a large swath of GOP voters, especially evangelical Christians, who had flocked to Huckabee in 2008. Evangelicals, more than other GOP voter groups, deeply distrust Romney because as Massachusetts governor, he once openly supported abortion and gay rights. And evangelicals dominate the primary process in Iowa, more than in any other early contest.

Whether Romney has any realistic opening to finish second, let alone first, in the "Hawkeye" state, is debatable. He's facing stiff competition from two Tea Party-backed Minnesotans, former Governor Tim Pawlenty and Representative Michele Bachmann, who as midwesterners, are far better-known in Iowa than Romney. Pawlenty has by far the best Iowa field operation of any GOP candidate, but has had trouble rallying party militants. And that's given an opening to the fiery Bachmann, who just so happens to be a native Iowan, and who's reminding Iowa voters of that every chance she gets.

Meanwhile, two other recently announced presidential candidates – Newt Gingrich and Herman Cain – have already beaten Romney to Iowa in search of former Huckabee supporters. Cain's been surging in various GOP state polls since the party's first official presidential debate in South Carolina two weeks ago. But he first got on the GOP radar screen last March when he delivered a rousing speech at a meeting of the Iowa Faith and Freedom coalition. A recent Zogby poll even has him leading the entire GOP field, slightly ahead of Romney

Romney's Iowa visit is not without risk. Having invested in the state, however marginally, he's now under some pressure to perform, and to make a respectable showing. Romney won the Iowa "straw poll" in 2007, but still ended up losing to Huckabee in the caucuses the following year. In Des Moines, before his speech abruptly ended, he rankled audience members by refusing to commit to competing in this year's straw poll, scheduled for mid August. But Romney's right: a poor showing in the straw poll would almost surely raise fresh doubts about whether his strength in the party extends beyond New England and parts of the southwest – and if not, whether he's really viable nationally.

Romney appears to be counting on the rest of the GOP field remaining bogged down in conflicts over the same shares of the GOP electorate, while he relies on his superior organisation and financing to slowly win over those who remain uncommitted. Romney certainly has history on his side. The GOP, far more than the Democrats, typically chooses as its new standbearer the candidate who finished second in the last presidential campaign cycle. That's how Ronald Reagan got the nomination in 1980, Bob Dole in 1996, and John McCain in 2008.

Dole, by most accounts, was not the most competitive GOP candidate to put up against Bill Clinton in 1996, but in keeping with party tradition he got the nod anyway, and promptly lost to Clinton in a landslide.

But Romney's party support, nationally and in key states, is clearly soft. For example, a recent Suffolk University (Boston) poll gave him 29% of GOP voter support, compared to single-digit percentages for his competitors, including just 9% for his closest competitor Sarah Palin, who's apparently still on the fence about whether to join the race (despite her upcoming national bus tour).

With such a commanding lead – in effect, three-to-one over his nearest GOP rival – you might think that Romney's a virtual shoo-in, at this point. But nine of ten survey respondents said they had not firmly committed to any candidate, including Romney, and 40% said they were still hoping that a fresh GOP face would enter the contest. Even in New Hampshire, which some GOP candidates have all but ceded to Romney, the latest polls show that his support, while broad, is tepid, with just 4% firmly committed to voting for him.

If you don't think this race is still wide open, consider the latest CNN poll, conducted just before Romney left for Iowa. Romney finished second this time, garnering 15% of the GOP vote, with a handful of candidates, including Palin and Cain, also in double-digits, nipping at his heels. And the winner with 16%? None other than former New York mayor Rudy Giuliani, who says he's flirting with another run, despite having embarrassed himself in 2008 by failing to secure a single party delegate.

With an electorate this discontented – and a president still this vulnerable, despite his recently improved favourability ratings – you'd think Republicans seeking the White House could come up with a better idea than to kick their 2008 runnerup candidate to the curb in favour of their last-place finisher. Maybe it's a sign of how little real vision and leadership is emerging from the GOP this year, notwithstanding its sound and fury.