Donald Trump implored his supporters Sunday to brave frigid temperatures and deliver him a decisive victory in Monday鈥檚 Iowa caucuses, saying their vote would help bring to Washington the retribution he has repeatedly promised if he returns to the White House.

The former president has set sky-high expectations for his own performance in the first contest of the race for the Republican presidential nomination. He spent the day before the caucuses trying to ensure he meets them. His main GOP rivals all spent Sunday in Iowa as well, making last-minute appeals to Iowans open to hearing them.

At a rally in Indianola, Trump said his supporters could fight back against his political enemies, claiming that the four indictments he faces were driven by politics and renewing his false claims about the 2020 election he lost to Democrat Joe Biden.

Many in the crowd wore white and gold caps identifying them as Trump caucus captains who will help round up support for him Monday night.

鈥淭hese caucuses are your personal chance to score the ultimate victory over all of the liars, cheaters, thugs, perverts, frauds, crooks, freaks, creeps and other quite nice people,鈥� Trump told the audience. 鈥淭he Washington swamp has done everything in its power to take away your voice. But tomorrow is your time to turn on them and to say and speak your mind and to vote.鈥�

More than 30 minutes before the doors opened for Trump鈥檚 rally at Simpson College, Marc Smiarowski said he planned to do just that.

鈥淚鈥檓 here in part out of spite,鈥� said the 44-year-old public utility worker who drove 40 miles from Huneston to see Trump. 鈥淚 can鈥檛 abandon him. After what they did to him in the last election, and the political persecution he faces, I feel like I owe him this. He鈥檚 our only option.鈥�

He was among more than 100 layered in Carhartt coveralls with hats and hoods pulled down tight to fight off the minus 18-degree Fahrenheit (minus 28-degree Celsius) chill. It was a test run for Iowa鈥檚 caucuses Monday night 鈥� and of the devotion Trump said last week would make his supporters 鈥渨alk on glass鈥� for him.

Even as he predicted his supporters would deliver a substantial victory over his nearest rival, he sought to temper expectations that he could cross 50% of the vote, a threshold never crossed in a contested Republican caucus. The previous record for a margin of victory was Bob Dole鈥檚 nearly 13-point win over Pat Robertson in 1988.

Both former U.N. Ambassador Nikki Haley and Florida Gov. Ron DeSantis, who has bet big on Iowa, exuded confidence in national interviews as they compete for a caucus showing that will boost their campaigns even if they don鈥檛 beat Trump.

The final Des Moines Register/ NBC 亚洲天堂 poll before Monday鈥檚 caucuses found Trump maintaining a formidable lead, supported by nearly half of likely caucusgoers, compared with 20% for Haley and 16% for DeSantis. Haley and DeSantis remain locked in a close battle for second.

鈥淲ith our folks, they鈥檙e committed, they鈥檙e gonna be there,鈥� DeSantis said on CNN鈥檚 鈥淪tate of the Union,鈥� noting that the Republican calendar doesn鈥檛 end with Iowa. 鈥淲e鈥檙e going to have a good night.鈥�

The sun was out across Iowa, but some streets and highways remained covered in snow from a Saturday blizzard. Temperatures stayed below 0 degrees Fahrenheit all day and were not forecast to rise into positive territory until Tuesday. The weather 鈥� by far the coldest since Iowa started leading the presidential selection process in 1976 鈥� continued to disrupt plans.

Because of travel conditions from Des Moines, Haley canceled a Sunday morning stop in the eastern city of Dubuque about an hour before it was to start. She swapped in a virtual town hall.

Voters walking into the venue were given the news by campaign staffers, who offered some a T-shirt, hat or yard sign as consolation.

鈥淚 don鈥檛 blame her,鈥� said John Schmid, 69, a retiree from Asbury, a few miles outside Dubuque. He is a Haley supporter but wanted to see the 鈥渞efreshing鈥� candidate in person. He hopes Haley will do well in the caucuses, which he will attend despite the bitter cold.

鈥淚t鈥檚 just part of living in Iowa in January,鈥� he said.

Haley did make it to an event in Ames, a college town much closer to Des Moines.

鈥淚t鈥檚 been 11 months, and it comes down to tomorrow,鈥� Haley said of Monday鈥檚 votes, repeating her frequent call to GOP voters to elect her as a 鈥渘ew generational leader that leaves the negativity and the baggage behind and focuses on the solutions of the future.鈥�

Trump continued picking up support from Republicans who鈥檇 remained on the sidelines. , who ran for the GOP nomination himself but failed to catch fire, and Florida Sen. Marco Rubio endorsed him Sunday. In picking Trump, Rubio passed over DeSantis, the governor of his home state, and Haley, who endorsed Rubio at a crucial moment in his own unsuccessful 2016 presidential campaign.

Some voters, too, were waiting until the last minute to make up their minds.

Judy Knowler, 64, of Peosta, had hoped to see Haley in person to help her make up her mind.

鈥淚 have one foot in Nikki鈥檚 camp but we鈥檒l see,鈥� she said in Dubuque. 鈥淚t鈥檚 an opportunity most Americans don鈥檛 get to be this close in person.鈥�

After his rally, Trump dropped by a Casey鈥檚 convenience store in Waukee with Burgum, where he picked up two pizzas and briefly chatted with reporters. 鈥淏ig day, I think, for our country,鈥� he said. 鈥淎s you can see there鈥檚 been tremendous enthusiasm.鈥�

He later stopped at a firehouse, where he talked with firefighters about their trucks, posed for photos and asked for a slice of the pizza they were eating.

Fingerhut reported from Dubuque, Iowa, and Cooper reported from Phoenix. Associated Press writers Jill Colvin in Indianola, Iowa, and Meg Kinnard in Des Moines, Iowa, contributed to this report.

Thomas Beaumont, Hannah Fingerhut And Jonathan J. Cooper, The Associated Press