DES MOINES — It's Ted Cruz or Donald Trump. The Harvard Law graduate knows something about closing arguments and that was the clear takeaway from the Cruz presidential campaign rally on the eve of the Iowa caucus.

"Election after election, Washington wants conservatives to be divided," Cruz said at the Iowa State Fairgrounds Sunday night. "What we see is conservatives standing together."

But most of the warm-up speakers at the Cruz rally took repeated shots at Trump and argued that the Texas senator was the only candidate who can beat him in the caucuses.

"This race is down to Ted Cruz and Donald Trump," said Iowa social conservative leader Bob Vander Plaats. "No matter who you support, if you are not comfortable with Donald Trump as the nominee, you need to vote for Ted Cruz."

Trump had launched a series of attacks against Vander Plaats on Twitter last week. At Cruz's rally, Vander Plaats returned the favor.

After saying that the Bible passage Exodus 18:21 reminded him of Cruz, Vander Plaats joked to the audience, "Exodus is well in front of Second Corinthians," the New Testament book whose name Trump flubbed when he spoke at Liberty University.

Vander Plaats didn't stick to veiled shots. After saying Trump's comments about hypothetically shooting people on Fifth Avenue without losing votes reflect "a judgement and temperament that have no place in the White House," he assailed the billionaire as unreliable on a whole host of social issues important to conservative Christians.

"Life is not up for the art of the deal," he said, referencing the title of Trump's book and his penchant for deal-making. "Marriage is not up for the art of the deal. Religious liberty is not up for the art of the deal."

Ginni Thomas, the Tea Party leader who is married to Supreme Court Justice Clarence Thomas, compared Trump to Barack Obama. "People filled 'hope and change' with whatever they wanted to hear," she said of Obama in 2008. "That is true of another candidate."

Like Vander Plaats and other speakers, Thomas pointed to reports that establishment Republican figures preferred Trump to Cruz. "The snakes are out," she said. She criticized Trump as an unprincipled deal broker.

"Let's make America great with the right candidate," Thomas said, riffing on Trump's campaign slogan.

Iowa conservative commentator Steve Deace said that judgment transcended even conservatism and the Constitution as an important factor in casting one's caucus vote. "A 70-year-old man who tweets like he's got Bieber fever is not a president of the United States." It would be a "hell of reality show," he added, but not a good way govern the country.

"Is this a tantrum or an election?" Deace asked.

Rep. Steve King, R-Iowa, said Cruz "has a dozen or more congressional endorsements. Trump, goose egg." King then pointed out some of Cruz's congressional supporters who were in the audience, such as Rep. Mo Brooks, R-Ala., and Rep. Alex Mooney, R-W. Va.

King told a story about Cruz being asked how he would deal with Senate Majority Leader Mitch McConnell as president. "With delight," King quoted Cruz as saying.

Even Cruz himself responded to a possibly intoxicated heckler, "Is that Donald Trump yelling in the back?"

For months, Cruz was the most reluctant of the top-tier Republican candidates to go after Trump, preferring instead to woo his supporters. The Texan has also faced spirited competition for conservative votes from Marco Rubio.

Rubio wasn't ignored at the Cruz rally. Deace also tore into him, saying the big "test of [the Florida senator's] readiness to be president was the Gang of Eight" immigration deal.

Deace said Rubio tried to persuade him the Gang of Eight was a good idea. "A great idea for people breaking the law," the radio host scoffed, asking, "Why is compassion always measured" by helping "people who break the law" rather than the law-abiding?

Rubio, Deace argued, "chose the system over us."

King took on Rubio's argument that Cruz is a flip-flopper. He said it was ridiculous to contend that Cruz had calculated or "moved on principle."

Heidi Cruz, the senator's wife, listed three reasons she fell in love with him. They included his steadfastness and willingness to challenge the status quo.

The whole "Trust Ted" theme also pushed back against Rubio's narrative that Cruz can't be trusted.

Part of the contrast with Trump was also aimed at other candidates besides the billionaire. By setting up a binary choice, Cruz supporters hope to sway evangelicals who might still be in Ben Carson's camp or libertarians voting for Rand Paul. A video shown before the speeches began highlighted Ron Paul supporters who were now with Cruz.

But with hours to go and the Iowa caucus on the line, team Cruz was treating Trump as the biggest obstacle to victory.