COUNCIL BLUFFS, Iowa — Since the night Donald Trump won in 2016, Democrats have wondered: How can we beat him?

Would they need an exciting liberal agenda? A more moderate approach? A fresh face? A familiar one? A woman? A white man? A person of color?

Monday in Iowa, they’ll start answering those questions.

The Iowa caucuses that night will provide the first actual votes after months of speculation and debate, sending a signal that could ripple through other states that follow in quick succession. The results won’t settle the Democratic nomination, but they could establish a clear front-runner, cull some high-profile hopefuls, or vault an underdog upward.

Or, with several candidates bunched near the top of the polls and a new, potentially confusing method of reporting results, Iowa could also create a jumble that presages a long, drawn-out fight.

Seven of the last 10 Democrats to win Iowa have gone on to become the party’s nominee, including every winner since 2000. But Iowans can remember few parallels to the number of options and level of uncertainty this year, all amplified by an overriding desire to unseat Trump.

“The race is exceedingly close and fluid," said Jeff Link, an Iowa Democratic strategist. "Probably closer and more fluid than it’s been in a long time.”

The event arrives amid a roller-coaster stretch including the Super Bowl Sunday, the caucuses Monday, Trump’s State of the Union on Tuesday, and a final vote set for Wednesday in his impeachment trial.

No candidates have more riding on Iowa than former Mayor Pete Buttigieg of South Bend, Ind., and Sen. Elizabeth Warren, of Massachusetts. Each surged early and has been part of a foursome atop the polls. But both have faded more recently, and need strong showings to jolt their campaigns as former Vice President Joe Biden and Sen. Bernie Sanders of Vermont have pulled ahead.

With Biden and Sanders looking like strong favorites in the states that follow, Buttigieg and Warren have invested heavily in Iowa, hoping to show they, too, can win, and to build momentum.

Buttigieg, speaking to a crowd of about 400 Friday in Council Bluffs, near the Nebraska border, explicitly contrasted himself with Biden and Sanders, urging a turn to a new generation.

Biden “will say that we cannot take a risk on someone new,” Buttigieg said. “I would argue that what history has taught us is that in a moment like this, we cannot take the risk of trying to fall back on the old playbook and rely on the familiar to deal with a fundamentally new challenge.”

And he warned that Sanders’ calls for rapid, revolutionary change risk alienating majorities who are otherwise ready to throw out Trump and embrace Democratic ideas on expanding health care, fighting climate change, and making college more affordable.

“We actually have an opportunity to energize, not polarize, that majority, not only to win the election but in order to govern what will be a dangerously divided nation,” he said from a small stage.

Several Iowa Democrats said in interviews this week that they’re thinking about who can win swing voters, the kind of people who flipped from Barack Obama to Trump in places like Northeastern Iowa — and who resemble those who tipped key states like Pennsylvania, Michigan, and Wisconsin.

» READ MORE: Pennsylvania is critical in 2020. Here’s how Trump could win or lose it.

The closing arguments reflected that focus on winning above all else.

Warren, long seen as a liberal fighter for big policy plans, released a set of ads Friday portraying her as the candidate who can unify the progressive and establishments wings of her party. One spot features a trio of Warren supporters who each backed Hillary Clinton, Sanders, or Trump in 2016. "We can’t afford a fractured party,” one of her supporters says.

The senator, one of several candidates held in Washington during the impeachment trial, dispatched allies across Iowa, including her golden retriever, Bailey.

In an airy Des Moines event space with open ductwork, Warren’s husband, Bruce Mann, spoke for the senator before a crowd of around 700 Friday night, along with three House members supporting the senator.

Rep. Katie Porter (D., Calif.), who stressed that she recently won a previously Republican-held district in Orange County, said Warren "can reach into every pocket of our community — rural, urban, white, brown, black, young, old, LGBTQ,” adding: “I represent a Republican district and I am all in for Elizabeth Warren.”

Iowa sends a signal — but maybe a mixed one

A relatively tiny fraction of Democratic delegates are at stake in Iowa.

But the first results "send a signal to the rest of the party ... about what real, on-the-ground party activists think,” said Dennis Goldford, a political science professor at Drake University in Des Moines.

» READ MORE: From an Iowa kitchen, the crazy but kind of reassuring path toward the presidency

That signal might be harder to interpret this year.

In a new twist, Democrats will release not just one result, but three — potentially leading to competing arguments over who did best.

As usual, the party will tally the “state delegate equivalents” each candidate wins. But now they’ll also release the results of two caucus “alignments” — one when caucus-goers pick their first choices, and another when those supporting lagging candidates get a chance to switch to a second choice.

» READ MORE: How the Iowa caucuses work

One candidate could win the most first-choice support, but another might lead when first and second choices are considered. Both might declare victory.

With polls suggesting a tight race, if “you find the top three, top four are a whisker’s width away from each other, then the caucuses decide nothing,” Goldford said.

The expectations game

Much depends on a candidate’s perceived stature.

“Every caucus participant has exactly the same opponent, and that opponent’s name is ‘expected,’ " Goldford said. “The central question is: Did you do better than expected or worse than expected?”

Polls suggest Biden and Sanders are ending the Iowa campaign where they started, on top. If either wins, he would become the clear front-runner.

Strong support for Sanders in New Hampshire and Nevada, and for Biden in South Carolina — all states that vote in February — also means they could survive a disappointing Iowa finish. Still, if Sanders slips, it could reinforce concerns about his appeal beyond his fervent base. A Biden flop might dent his central argument that he is the most electable.

The Bloomberg factor

If anyone else cracks the top four, it would shake up the race and potentially decimate whichever front-runner fell to fifth. Many Iowa insiders say Sen. Amy Klobuchar, a moderate from neighboring Minnesota, has the best chance of a surprise breakthrough.

Looming in the background is Michael Bloomberg, the billionaire former New York mayor. He’s sitting out Iowa and other early voting states while spending more than $200 million elsewhere, including more than $10 million in Pennsylvania — setting himself up as an alternative if no one can establish a clear lead, or if a liberal such as Sanders emerges as the front-runner.

Democratic eyes across the country will be watching. It’s so close, Buttigieg said, “we can taste it.”