Nearly 200,000 mostly stalwart and predominantly evangelical Iowa Republicans will brave frigid cold weather and snow on the ground tomorrow evening to officially kick off the 2024 Republican presidential nominating contest.

Public opinion polls already tell us former President Donald Trump will be the likely winner. The only question is what his percentage of the statewide vote will be. It should be somewhere between 45% and 60% – probably in the middle of that at just over 50%.

Iowa Republicans hold their caucuses at 7 p.m. on a Monday evening in a local church hall or the gymnasium of a neighborhood public school. After briefly discussing the various candidates for the Republican nomination, each person writes their choice on a small piece of paper and turns it in, or something like that.

The results from each caucus are telephoned to the state capital in Des Moines and added up to get the statewide results and be put on national television.

The Republicans have the Iowa caucuses all to themselves this year. The Democratic National Committee cancelled the Democratic caucuses, made them a presidential primary and moved them to March 5, Super Tuesday.

Stay up to speed: Sign up for daily opinion in your inbox Monday-Friday

Iowa caucuses have often yielded surprise first-place winners. In the Republican caucuses, George H. W. Bush beat Ronald Reagan in 1980, U.S. Sen. Ted Cruz defeated Donald Trump in 2016, and U.S. Sen. Rick Santorum bested Mitt Romney in 2012. In the Democratic Party Iowa caucuses in 2020, Pete Buttigieg defeated current U.S. President Joe Biden.

This time around, thanks to polling, we think we know Trump is the winner. What we do not know is who will come in second. Former Gov. Nikki Haley of South Carolina has surged ahead of her fellow Trump challengers in New Hampshire and seems to have been gaining in Iowa over the past few weeks. She has bested Florida Gov. Ron DeSantis in Iowa in recent polling.

DeSantis has “bet the farm” on farm-filled Iowa. He has campaigned in all of Iowa’s 99 counties. He has won the endorsement of Iowa’s popular Republican Gov. Kim Reynolds. And he has definitely improved his debating skills over the past few weeks.

It is hard to do regular systematic polls of the Iowa caucus goers. A chunk of them remain undecided almost to the end. It is never clear in the Hawkeye State who will show up at their caucus to vote. And wintry weather will be a factor this year, although hardy hardcore Republican Iowa activists will get to their caucus and vote no matter what the weather.

Former New Jersey Gov. Chris Christie ended his campaign for president a few days ago. He mainly campaigned in New Hampshire and might have come in third or fourth in New Hampshire.

But Christie totally skipped Iowa. What few supporters he had in Iowa will probably cast their vote in the Iowa caucuses for former Gov. Haley. But Christie did not have enough support in Iowa for that to make much of a difference.

Ohio businessman Vivek Ramaswamy is also running in the Iowa Republican caucuses. We predict he will come in a distant fourth in this race. His policy views are either too similar to Trump’s, or sound too simplistic, or appear to be conspiracy theories.

The big question to be answered in the 2024 Iowa caucuses is: Can Nikki Haley beat Ron DeSantis and by how much? The two have become bitter antagonists this past month before Monday.

Haley charges that DeSantis has frequently lied about her record and his achievements. She acknowledges DeSantis has been a good governor of Florida but faults him for his lack of support for Ukraine in its war with Russia. Haley also accuses DeSantis of flip-flopping on issues such as Social Security reform.

Haley will be doing well if she can beat DeSantis by several percentage points in Iowa. If Haley can win about 24% of the statewide vote to about 16% for DeSantis, his campaign for the 2024 Republican nomination for president will be largely over.

If Haley gets a strong second-place finish in Iowa, that will give her what is called an “Iowa bounce.” That will give a big extra boost to her campaign in the New Hampshire Republican primary eight days later.

Haley has done well in New Hampshire, a more moderate state than Iowa with less agriculture and fewer evangelicals. Some polls have her within 10 percentage points of Donald Trump in New Hampshire.

Although Christie did not endorse Haley when he ended his campaign, we expect many of Christie’s former New Hampshire supporters will likely vote for Haley in the upcoming New Hampshire Republican primary.

Thus, Iowa is a make-or-break state for DeSantis. If he comes in a dispiriting third, it is all over for him. He has not campaigned much or attracted much support in New Hampshire. The popular Republican Gov. of New Hampshire, John Sununu, has enthusiastically endorsed and campaigned for Haley.

As noted, the Iowa caucuses have often resulted in surprises. This could happen again in 2024. If Trump does not win Iowa and Haley is a surprise victor in the caucuses, she will head to New Hampshire with great momentum.

On the other hand, if DeSantis comes in a solid second to Trump, DeSantis gets to stay in the race for at least a few more weeks.

What if it is Trump who scores a big surprise in Iowa by finishing with 60% or more of the statewide vote? There will probably be no way of stopping him from winning most of the remaining Republican primaries and caucuses.

Why is Donald Trump doing so well in Iowa? Many of the likely caucus goers there are evangelicals, and they were pleased with Trump’s appointment of conservative anti-abortion judges to the U.S. Supreme Court. Also, many of the Republican caucus goers support his tough-on-China, tough-on-NATO, and tough-on-bureaucratic-regulation policies.

Trump and DeSantis have shared isolationist-leaning policies. Haley is more of an old school Republican internationalist, not likely to be popular with midwest Iowa isolationists.

Donald Trump is well on the road to the Republican presidential nomination. His rivals do not seem to have altered his dominant position in the Republican Party. If he is to be slowed in his march to the nomination, it will have to happen in New Hampshire rather than Iowa.

Here is what to watch for on Iowa caucuses night as the returns come pouring in: How big a percentage of the statewide vote is Trump receiving? Is Nikki Haley coming in a strong second? Will Ron DeSantis finish a weak third and be knocked out of the race?

Tom Cronin and Bob Loevy are news columnists who write about Colorado and national politics.