(Photo by Jude Joffe-Block - KJZZ)

Donald Trump supporters at a Phoenix rally in July 2015.

(Photo by Jude Joffe-Block - KJZZ)

Republican presidenial candidate Sen. Ted Cruz held a rally in Phoenix on Friday.

All eyes are turning to Arizona as Republicans here are poised to cast ballots Tuesday in what is shaping up to be a very unusual presidential primary season.

As Arizona Republican voters prepare to go to the polls or turn in early ballots, many are aware of the possibility that no GOP candidate this primary season will win 1,237 delegates — the number needed to clinch the party’s nomination heading into the Republican National Convention. That atypical situation would trigger a contested convention in Cleveland this summer, in which delegates would vote in multiple rounds until a candidate emerged as the winner.

Donald Trump is leading with 678 delegates, Texas Sen. Ted Cruz has 423 and Ohio Gov. John Kasich has 143.

At this point, with 1,049 delegates left, it’s impossible Kasich can get to 1,237. It’s pretty unlikely for Cruz. It’s plausible — but not at all certain— Trump will hit that number.

Professor Fred Solop of Northern Arizona University said that makes Arizona’s March 22 contest important for the next phase of Trump’s campaign.

Arizona is a winner-take-all state for Republicans, and Trump is favored to take all 58 delegates. Solop said if Trump can keep his momentum going and keeps winning, he will have enough delegates to walk into the convention and win the nomination in July.

But Solop said it’s also possible Trump will lose some key states and fall short of 1,237 delegates.

“And then we have a floor battle taking place.” Solop said. “Donald Trump is already making noise about the convention saying that his people will riot if he is denied the nomination.”

This past Saturday, thousands turned out to see Trump speak in Fountain Hills.

“Are we winning or what?” Trump asked the crowd, as they cheered back. “Look at the numbers. Man!”

He spoke about his lead over his main rival, Cruz, who he called “Lyin’ Ted.”

“Then I hear Cruz the other day saying, ‘I am the only one who can stop Trump.’ You ever hear this guy? ‘I’m the only one, I beat him five times,’” Trump said. “And I said wait a minute, I beat [Cruz] 20 times, what is going on?”

In fact, heading into Tuesday's race, Trump won the most delegates in 19 states and one territory and Cruz in 8 states and one territory.

Supporters like Wendy Dahlmann, a Fountain Hills insurance agent, expressed concern Trump could be unfairly denied the nomination by Republican party leaders.

Dahlmann said the crowded Republican field this year made it too difficult for any one candidate to win 1,237 delegates. She said Trump should automatically be made the nominee if he has the most delegates heading into the convention.

“If they end up going to a brokered convention, I will go down to the Republican headquarters and rip up my Republican card,” Dahlmann said. “I will leave the party.”

Dahlmann said she has been supporting Trump since he announced his candidacy and she believes his business savvy is needed to turn the country around.

Dahlmann said she fears if Trump doesn’t win 1,237 delegates before the convention, Republican leaders will try to nominate someone favorable to the Republican establishment. A rule put in place for the 2012 convention bars anyone from being considered for the nomination who has not won the majority of delegates in at least eight states, but a change to that rule could open up who could vie for the nomination.

The polarization around Trump's candidacy has many Republican strategists concerned about Trump’s chances in a general election.

Cruz pointed out his rival’s potential electability challenges at a Friday night rally at Arizona Christian University in Phoenix.

“I agree with the 65 to 70 percent of Republicans who say if Donald Trump is our nominee it is a disaster, that Trump loses to Hillary and we lose the whole country,” Cruz told his supporters.

The Texas senator told the packed student center that his own campaign still had a chance of winning 1,237 delegates before the convention. Or, if neither he nor Trump got to that magic number, Cruz said he could win a contested convention when delegates move on to a second round of voting.

Cruz said his chances were bolstered by Florida Sen. Marco Rubio dropping out.

“The overwhelming majority of those Rubio supporters have come and are supporting us, so we keep getting stronger and stronger,” Cruz said.

Kathy Davis is one of those former Rubio supporters who switched over to Cruz in the last week. The Phoenix real estate agent liked what she heard from Cruz on Friday.

“Cruz is a strong constitutionalist,” Davis said. “I have the utmost confidence in voting for him, I don’t for Trump.”

Davis said she doesn’t trust Trump and doesn’t believe he has a moral compass.

Still, Davis thinks Trump and Cruz should be the only contenders for the party’s nomination at the convention. She opposes any rule change that would anyone else to be considered for the nomination.

“That wouldn’t work,” Davis said. “That doesn’t mean I will vote for Trump later, I just think the convention needs to be solid convention and there shouldn’t be any monkey business.”

But the fact that Republican voters like Davis could choose to stay home if Trump is the nominee, while some Trump supporters are threatening to renounce the Republican party if they feel Trump is denied the nomination, shows why this primary season is turning out to be such high stakes for the GOP.

EDITOR'S NOTE: Story has been modified to reflect that John Kasich is the current governor of Ohio; and information about the number of states each candidate has won so far.