Fidel Castro called it "the greatest competition of idiocy and ignorance that has ever been," and as the Republican nomination contest rolls into Florida, it is surprising how many conservatives agree with him.

Few would admit it agreeing with American's bete noir, of course – in the first Florida debate, Mitt Romney declared he would authorise covert CIA operations to bring down the Cuban regime and Newt Gingrich said Castro is headed to hell – but presented with these two flawed candidates, a growing number of influential Republicans are inclined to choose neither.

Currently Romney stands nine points ahead on the latest Florida opinion poll.

"I am a firm believer that primaries make stronger candidates," wrote Eric Erickson, on his popular Red State website, ahead of Tuesday's pivotal Republican primary in Florida. "But at some point you just have to stand back, take a sip of bourbon, and sigh 'damn' under your breath as you behold the carnage being wrought within the Republican Party."

The shortcomings of Michele Bachmann, Herman Cain and Rick Perry have been brutally exposed. Ron Paul supporters are energised as much by his promise to legalise drugs and bring American troops home as his unshakeable fiscal conservatism. Rick Santorum has admitted that he is only staying in the race in the hope that Gingrich's campaign will implode. The Big Two – Romney and Gingrich – have been trading blows since South Carolina, with no knock-out in sight.

Romney, long perceived as the inevitable nominee, has rarely looked so vulnerable. Releasing his tax returns was designed to defuse the issue of whether his enormous wealth has been amassed at the expense of ordinary Americans, but on the same day that Barack Obama called income inequality "the defining issue of our time," in his State Of The Union address, it only served to highlight Romney's difficulty attracting middle-class and working-class support.

In South Carolina, Romney won more votes from those earning more than $200,000 a year than Gingrich, beating him 47% to 32%. But among households with incomes between $50,000 and $100,000 the positions were reversed, the former Speaker winning 41% to 25%. Voters from families earning less than $50,000 a year also strongly preferred Gingrich, by 42% to 22%.

This was not an isolated result: even in New Hampshire, where he won comfortably overall, Romney failed to convince many low-income voters to turn out for him. Gingrich has toned down his attacks on Romney's record at Bain Capital, but he is still exploiting the wealth gap at every opportunity. Asked an unrelated question about Romney's position on immigration, he replied: "You have to live in a world of Swiss bank and Cayman Island accounts and be making $20 million for no work, to have some fantasy this far from reality."

SINCE his South Carolina drubbing, Romney has taken a more aggressive stance, assailing Gingrich for his consultancy work at government-backed mortgage lender Freddie Mac, and reminding voters that the last time his rival held office, he was drummed out of Congress in disgrace. The $1.6m paid to Gingrich on the eve of the housing crash is a sensitive issue in Florida, which was among the states worst affected by the crisis.

A new poll shows how much damage is being done: only 31% of the people surveyed had a favourable view of Romney, compared with 49% who view him unfavourably. Gingrich's numbers were even worse, at 29% to 51%. It is telling that there have been so few high-profile endorsements: among the Grand Old Party's 75 current Governors and Senators, Romney has been endorsed by nineteen, Gingrich just two. The remaining 54 are uncommitted. In Florida, both campaign teams covet charismatic young Hispanic Senator Marco Rubio but he will not give either his blessing. However, it appears that Romney has stronger support than Gingrich among Florida's influential Latino community.

From the start of the nomination contest, there have been attempts to draft alternative candidates: New Jersey Governor Chris Christie, Sarah Palin, Congressman Paul Ryan, even Rubio. The latest speculation concerns Indiana Governor Mitch Daniels, who delivered a measured, quietly impressive response to Obama's speech. Never mind that Daniels has been asked before, and declined, saying he has no wish to spend his life on the campaign trail.

Joe Scarborough, a former Republican Congressman from Florida who presents the morning news on MSNBC, told viewers to expect a drawn-out struggle. "I've been talking to the most powerful conservative movers-and-shakers in Washington over the past couple weeks," he said. "Every one I've spoken to is trying to figure out a way to get to a brokered convention." In that scenario, no candidate wins a majority of delegates, freeing state representatives to reassign their vote, until a compromise nominee is reached.

"Surely there is someone out there that both the Romney supporters and Newt supporters can agree on who is not named either Romney or Newt," concluded Erickson.