"I trust the people of Indiana to differentiate ... We are not a bitter, angry, petty, bigoted people. That is not America. I reject that vision of America," Cruz said in Osceola. "We are not an angry, ugly people, and the people of Indiana -- the people of Indiana have good judgment, have good values. The people of Indiana are the heartland of this country, and we have a choice -- we have a choice about our national character; who we will be."
After more than a week of hyping the importance of the Hoosier State's Tuesday primary, anything short of a win would be an embarrassment for the Texas senator -- and a sharp blow to his chances of holding Trump short of the 1,237 delegates he needs to clinch the Republican presidential nomination. He's thrown everything he's got into the race, taking the unusual step of announcing Fiorina as his running-mate and securing the endorsement of Gov. Mike Pence.
Trump, meanwhile, has scheduled two more large rallies after casting Indiana as his chance to deliver Cruz a knock-out blow on Sunday.
"Indiana is so important and we have to win it," Trump said to a crowd of approximately 1,500 people packed into a theater in Terre Haute, Indiana. "If we win Indiana, it's over."
The contest comes as Americans are increasingly convinced that Trump and Hillary Clinton will square off in the general election. A CNN/ORC poll found
that 84% of voters nationwide think Trump will lead the Republican ticket in November, while 85% say the same about Clinton on the Democratic side.
Trump is backed by 49% of Republicans nationally, compared to 25% for Cruz and 19% for Ohio Gov. John Kasich. Among Democrats, 51% back Clinton, while 43% support Vermont Sen. Bernie Sanders.
Cruz's jam-packed schedule reflects the do-or-die nature of Indiana's primary.
He has five events on his schedule for Monday: The breakfast stop in rural Osceola; a visit alongside Pence in Marion; a rally with Pence in the heavily evangelical Fort Wayne; a stop in Bloomington, home of Indiana University; and a nighttime rally in Indianapolis.
He has also dispatched Fiorina, who would become his vice presidential running-mate if he won the GOP nomination, to five events of her own in the counties surrounding Indianapolis.
Those suburban counties are favorable to Republicans, but tend to be more moderate than Cruz. They could be more ideologically inclined to support Kasich, and therefore perhaps the most important pool of voters in Indiana's primary.
Cruz has called in the cavalry, as well: Utah Sen. Mike Lee, Texas Rep. Louie Gohmert, radio host Glenn Beck and the candidate's wife, Heidi Cruz, are all hitting the trail.
Cruz told reporters in Osceola that even with a loss in Indiana, he'd continue his campaign.
"I am in for the distance," he said. "As long as we have a viable path to victory, I am competing to the end."
Cruz encountered a handful of hecklers in Marion, Indiana, during a stop at The Mill restaurant.
One particularly aggressive protester told Cruz he'd been mathematically eliminated from the GOP race and repeatedly yelled Trump's nickname for the Texas senator -- "Lyin' Ted" -- at Cruz.
Cruz went toe-to-toe with the man, asking him to name one thing that he liked about Trump. When the man named "the wall," Cruz cited Trump's meeting with The New York Times' editorial board.
"Hold on," Cruz said. "He told the New York Times editorial board he's not going to build the wall or deport anyone."
The man shouted his response: "Lyin' Ted!"
"Civilized people don't yell," Cruz responded. "With respect, Trump is deceiving you. Playing you for a chump. Ask yourself, why is it that the mainstream media wants Donald Trump to be the nominee?"
Trump has two big rallies planned for Monday: One in Carmel, a wealthy suburb of Indianapolis in voter-rich Hamilton County, and one in South Bend, a working-class, union-heavy city where his criticism of free trade deals could attract independent voters.
Before those events, Trump had lunch at Shapiro's, a downtown Indianapolis deli, where he at a reuben with his campaign team.
Vermont Sen. Bernie Sanders, meanwhile, is holding rallies in each of Indiana's three biggest cities: Evansville in the morning, Fort Wayne in the early afternoon and Indianapolis in the evening.
Two candidates aren't in Indiana at all on Monday.
Ohio Gov. John Kasich, who struck a deal with Cruz to skip Indiana in exchange for Cruz ignoring Oregon and New Mexico, is already campaigning on the West Coast.
And Hillary Clinton, the Democratic front-runner, has instead embarked on a tour of Appalachia, with stops in West Virginia and Kentucky -- two states that will vote in the Democratic primary this month -- and Ohio.
She held a rally in Indianapolis on Sunday before jetting to Detroit for an NAACP dinner.