Turnout is name of the game in today's Iowa caucuses

COUNCIL BLUFFS, Iowa -- In a final frenzy to inspire supporters to turn out for Monday's Iowa caucuses, presidential contenders scrambled to close the deal with the first voters to have a say in the 2016 race for the White House.

Even as the candidates begged backers to caucus, many hopefuls tried to lower expectations and look ahead to New Hampshire's Feb. 9 primary and later contests.

Republican Donald Trump, who has a slight edge over Ted Cruz in Iowa, predicted "many" senators would "soon" endorse him rather than their Texas colleague. Trump didn't name any such senators, and none emerged.

Trump also continued his attacks on Cruz, while Florida Sen. Marco Rubio, who is running third, pitched himself as the pragmatic choice for Republicans who want to win in November.

Vermont Sen. Bernie Sanders, meanwhile, sought to claim financial momentum in the race for the Democratic nomination, saying it has raised $20 million in January, suggesting he will continue to match front-runner Hillary Clinton's vast resources.

Democratic presidential candidate Hillary Clinton is embraced by a young member of the audience as they pose for a photograph at a rally at Washington High School in Cedar Rapids, Iowa.Andrew Harnik ~ Associated Press

One development -- the weather -- was beyond the candidates' control. Snowfall forecast for tonight appeared more likely to hinder the hopefuls in their rush out of Iowa than the voters.

Iowa offers only a small contingent of the delegates who will determine the nominees, but the game of expectations counts for far more than the electoral math in the state. Campaigns worked aggressively to set those expectations in their favor for Iowa, New Hampshire and beyond.

Several GOP candidates attended church services Sunday -- in part, a testament to the influence evangelical Christian wield in the Republican contest.

Trump attended a service in the non-denominational church First Christian Orchard Campus in Council Bluffs with his wife and two staffers. The billionaire took communion when it was passed, but he mistook the silver plates being circulated around the auditorium and dug several bills out of his pocket.

Cruz heard a Des Moines area minister urge politicians to treat their opponents with love. Pastor Mike Housholder of Lutheran Church of Hope even played two parody attack adds questioning the faith of church members.

Republican presidential candidate Ted Cruz speaks during a campaign event Saturday at Western Iowa Tech Community College in Sioux City, Iowa.Patrick Semansky ~ Associated Press

At a rally in Council Bluffs, Trump again took aim at Cruz. He hammered the senator for a recent mailer that suggests to recipients they have committed a "Voting Violation" by not being reliable caucus participants in the past.

"It is so dishonest. It is so dishonest," Trump said.

The Iowa secretary of state has also criticized the Cruz mailer, which the candidate himself has described as "routine."

Cruz directed much of his final advertising against Rubio as the senators' feud intensifies at the Iowa finish line.

Cruz took to the airwaves to challenge the conservative credentials of Rubio, the Floridian running third in Iowa, according to the polls.

Democratic presidential candidate Bernie Sanders poses for a selfie during a campaign rally Sunday in Waterloo, Iowa.Evan Vucci ~ Associated Press

One ad said of Rubio: "Tax hikes. Amnesty. The Republican Obama."

Rubio countered on CNN that Cruz is "always looking to take whatever position it takes to win votes or raise money."

Later, campaigning in Cedar Falls, Rubio downplayed differences among the GOP hopefuls.

"It's not just about who you like the most. It's about who gives us the best chance of winning. That matters," Rubio said at the University of Northern Iowa.

He did not mention his previous attacks on Cruz and Trump. Instead, he argued that "if in the end, policy differences are not enormous," then the question should be "who gives us best chance?"

The candidates' agreed on one thing: It's all about turnout now.

"If people come out to vote, I think you're going to look at one of the biggest political upsets in the modern history of our country," Sanders told CNN's "State of the Union."

Clinton said she had been subjected to "years of scrutiny, and I'm still standing." On ABC's "This Week," she said, "I feel vetted ... and I think I'm the best person to be the nominee and to defeat whoever they nominate in November."

Trump said "I don't have to win" in Iowa, before adding that he believes he has "a good chance" of victory.

Cruz said on "Fox News Sunday" that he's attracting "the old Reagan coalition" ranging from anti-establishment conservatives to working-class Democrats.

The last-minute scramble comes on the same day that campaigns will file campaign financial disclosures showing how much they've raised this month.

The Sanders campaign announced that it has raised more than $20 million this month. That means his pace is picking up. Earlier, his campaign said it raised $33 million over the last three months of 2015, compared to $37 million for Hillary Clinton's campaign in the same time period.

In the last major preference poll before the caucuses, Trump had the support of 28 percent of likely Republican caucus-goers, with Cruz at 23 percent and Rubio at 15 percent. The Iowa Poll, published by The Des Moines Register and Bloomberg, also found Clinton with 45 percent support to Sanders' 42 percent in the Democratic race. The poll was taken from Tuesday to Friday and has a margin of error of plus or minus 4 percentage points.