GOP presidential candidate Donald Trump speaks to the crowd at a campaign rally on January 27, 2016 in Gilbert, South Carolina
Des Moines (United States) (AFP) - Republicans scrambling to win the first contest in the US presidential nomination race geared for battle at Thursday's high-stakes debate in Iowa, but defiant frontrunner Donald Trump upended the campaign by refusing to attend.
Trump's gamble left the presidential race in uncharted waters days before Iowans vote February 1, but he insisted he will not back down in his feud with debate host Fox News.
The billionaire has doubled down, in a game of political chicken, hosting a rival event for military veterans at the same time as his own party showcases its candidates to Iowa voters.
All eyes are on the heartland state, where 12 Republican candidates and three Democratic hopefuls including Hillary Clinton are vying for both bragging rights and momentum as the primary race heads next to votes in New Hampshire, South Carolina and Nevada.
"The 'debate' tonight will be a total disaster -- low ratings with advertisers and advertising rates dropping like a rock. I hate to see this," tweeted Trump, who has never held elected office.
"I hope @CNN has enough bandwidth tonight because not many will be watching @FoxNews."
Adding to the spectacle, rival Mike Huckabee, the former Arkansas governor who is languishing in polls and was attending an undercard event before the main debate, said he will join Trump at his counter-event for veterans.
"It's not an endorsement of Donald Trump's candidacy; I'm still running for president," Huckabee assured CNN.
Another low-poller, former senator Rick Santorum, will also attend Trump's event.
Some veterans have denounced the fundraiser.
"Vets don't need political stunts. We need candidates to present smart, specific plans on VA (Veterans Affairs) reform," said Paul Rieckhoff, founder of the Iraq and Afghanistan Veterans of America.
- Trump streaks ahead -
Trump has accused Fox News, and especially debate moderator Megyn Kelly, of bias against him.
With Fox and the billionaire in all-out war, the Republican National Committee appeared eager to downplay the Trump snub.
"Every campaign is going to make the decision that they need to make" about debate participation, RNC chairman Reince Priebus told Fox News. "I think it's going to be a big night."
Analysts have been riveted by the unexpected drama and disruption of the typical Iowa political playbook. The last major candidate to skip a pre-Iowa caucus debate was Ronald Reagan, in 1980.
"Wow. What a chess game," Iowa State University political science professor Steffen Schmidt declared of the political theater.
But the longtime election watcher said he believed Iowa core conservatives were "furious" at Trump's flippant decision.
Trump has a genuine battle on his hands in Iowa with ultra-conservative senator Ted Cruz, his nearest GOP rival, who trails by about five percentage points in the RealClearPolitics average of recent Iowa polls.
Cruz, who has earned endorsements from key evangelicals and anti-abortion figures who tout his conservative and religious values, insists the race is winnable.
His team claims its ground game is second to none in Iowa, with 12,000 volunteers and staff blanketing the state.
Little is known about Trump's grassroots efforts to generate caucus turnout in Iowa, and he has largely avoided the grueling face-to-face courtship of voters, opting instead to talk to them from a distant podium.
Nationally, however, Trump keeps soaring. A recent CNN/ORC poll of Republican voters has Trump at 41 percent to 19 percent for Cruz, with more than two-thirds of Republicans saying they believe the billionaire developer will be the party's presidential candidate.
Florida Senator Marco Rubio is third at eight percent, followed by retired neurosurgeon Ben Carson at six percent and Florida ex-governor Jeb Bush at five percent.
- Cruz at center stage -
With Trump absent, Cruz will take center stage alongside six other Republicans eager for the opportunity to shine in the absence of the man accused of sucking the oxygen out of the room.
Cruz told Fox it was "stunning" that Trump refused to debate, challenging him to a one-on-one showdown.
Rubio meanwhile has denounced the Trump-Cruz sideshow. His final ad before Iowa portrays him as the electable Republican.
"This election is about defeating Hillary Clinton, and about saving what makes America unique," he says in the television spot.
The Donald is seeking to draw in Americans who have not voted for years, with the help of supporters like Julian Raven, an artist driving his larger-than-life painting of Trump across Iowa on a rented truck.
"He has guts," said Raven. "God votes Trump."