COUNCIL BLUFFS, Iowa — Donald Trump kicked off the final day before the Iowa caucus in a middle school gymnasium joined by his wife, daughter, and Jerry Falwell Jr., president of Liberty University and son of the deceased Christian televangelist.

Melania Trump told the crowd to vote for Trump because he will be the "best master negotiator," and an eight-months-pregnant Ivanka Trump added that she traveled to the Hawkeye State because of her love for her father.

Trump, however, quickly ramped up his attacks against Texas Sen. Ted Cruz and described the controversial mailer distributed by Cruz's presidential campaign as utterly "dishonest."

"It says voter violation, did you hear about this? Cruz issued a statement, put it in people's houses. Voter violation. Looks like a government voter violation," Trump said. "It is so dishonest. It is so dishonest."

But the Trump supporters who gathered in western Iowa largely appeared to choose the reality television star over Texas Sen. Ted Cruz for a different reason: immigration.

Iowa resident John Harold Halverson told the Washington Examiner he picked Trump over Cruz because Halverson believes the Texas senator hurt himself by formerly supporting increased levels of immigration and H-1B visa holders.

"I'm absolutely a Trump supporter," Halverson said. "Immigration is my No. 1 issue and Trump was the first one to talk about it."

Trump's view on immigration was also the decisive issue for Shael Jacobson-Smith, a Council Bluffs resident. She said she lost her landscaping business because of increased immigration. She also added that she was fearful of terrorists from the Middle East who "could come here and blow us up," but believed Trump understood how to prevent attacks from coming to Iowa.

Trump's ability to triumph at Monday's caucus could be dependent on his ability to grow voter turnout for the Republican caucus to record highs amid the news that another large winter storm could hit Iowa on Monday night. Trump appears poised to rely on his celebrity endorsements to help put him over the top and told the crowd that former Alaska Gov. Sarah Palin will campaign for him in Iowa on Monday, too.