DES MOINES — The Republican presidential candidates are meeting here Thursday evening for a crucial televised showdown ahead of the first votes of the 2016 campaign.

The seventh prime time and undercard debates, hosted by the Fox News Channel, are happening three days before the Iowa caucuses, and could serve as a pivotal turning point as the approximately one-third of voters who are undecided winnow their choices. The wildcard in a race that has already experienced its share of unpredictability is the presumed absence of frontrunner Donald Trump.

The New York celebrity businessman, in a tight race for the caucus crown with Texas Sen. Ted Cruz, has vowed to skip the debate. The move could divert attention from the debate and boost Trump, as have his many other of his unorthodox plays. It also runs the risk of alienating and Iowa GOP electorate that takes its first-vote status very seriously, and tipping the race to Cruz.

Some likely caucus-goers told the Washington Examiner that they believe that Trump is making a mistake, so much that they predicted he would ultimately show up and participate. "I don't think Trump is going to skip it; I'd be surprised if he does," said Ron White, 51, an insurance claims adjuster from Des Moines who plans to caucus for the first time but has yet to settle on a candidate. "It's hugely important."

Making the cut for the prime time debate were Trump; Cruz; Florida Sen. Marco Rubio; New Jersey Gov. Chris Christie; retired pediatric neurosurgeon Ben Carson; former Florida Gov. Jeb Bush; Ohio Gov. John Kasich and Sen. Rand Paul of Kentucky.

Trump plans to hold a competing event honoring military veterans that will be televised by rival cable news networks, and could siphon viewers from the face-off. Or the ratings could hold steady, and the remaining seven debate participants could benefit from more camera time to make their case to the voters. Trump backing out also is likely to alter how the candidates interact with each other.

For instance, absent the reality television star to occupy Cruz, his chief rival for Iowa, and Bush, who lately has defined his underdog candidacy as being the candidate most willing to criticize Trump, attention could turn to Rubio. Both Cruz and Bush have targeted Rubio because, although he's running third in most polls, his voters are important to the different coalitions they need. Cruz is trying wants Rubio conservatives; Bush wants the mainstream Republicans that like the senator.

How Rubio handles the onslaught, if it comes, could help determine the outcome of Monday's caucuses. Rubio plans to venture into the spin room and speak to reporters post-debate, his campaign told the Examiner, marking a first for the GOP contender since the candidates began debating last August.

"Marco didn't come to Des Moines to attack other Republicans. But if he's attacked, he'll be ready to respond, just like he has in all the previous debates," Rubio spokesman Alex Conant said

The latest polls out of Iowa show Cruz and Trump in a tight race, with the edge going to the New Yorker. Rubio runs third and is generally the only other candidate in double digits.

Veteran Republican operatives in the Hawkeye State conceded that Trump's power play to skip the debate — he blames Fox News for treating him unfairly — could work to his advantage, as has the other actions he's taken in this race that would have normally sunk a traditional politician. Some Republican voters who plan to caucus on Monday evening agreed, albeit reluctantly, that Trump might well be rewarded for bailing on the debate.

Asked if missing the debate would hurt Trump with undecided voters, Rubio supporter Susan Arnold, 68, of Urbandale, said: "I hope so."

Still, many other voters believe Trump has miscalculated, given the timing and location of this debate. This is the first such televised event of the 2016 Republican campaign to take place in Iowa, and it's scheduled for just four days before the caucuses. If Cruz still threatens Trump for first place, which both the Texan's operation and other campaigns believe, skipping out on this particular debate could cost the businessman.

That view is shared by experienced Iowa Republican insiders, who, on condition of anonymity, used words and phrases like "big mistake" and "insulting to Iowans" to describe Trump's decision. That explains why Cruz and Rubio both hammered Trump for dropping out.

Rubio did so briefly Wednesday evening during a campaign rally with 325 people in West Des Moines, calling Trump's theatrics a sideshow. Cruz, in a rally across town soon after, followed suit, although more vigorously. His opening remarks before a packed house of more than 500 were all about Trump skipping the debate. Cruz is challenging Trump to a one-on-one faceoff, and said he has reserved a venue for the event, to occur Saturday night, in the unlikely scenario that he accepts.

"What does it say when Donald tells the state of Iowa: My time is more important than your time," Cruz said.

Trump supporters aren't likely to have second thoughts about him just because he's skipping the debate. They believe in the billionaire and probably see his spat with Fox News, and his skipping the debate, as a power move that shows how he'd govern in the White House. Cruz supporters counter that it paints the picture of a man who is unfit for the Oval Office.

"Trump had the opportunity to stand before Iowans and to make his case, with all the hard questions and to prove before he is, before Iowans. And, he chose not to," said Tyler Dorin, 28, a mechanical engineer from Des Moines who plans to caucus for Cruz.