Republican presidential candidates weighed in on immigration, the Islamic State, criminal justice reform and — of course — Donald Trump at the Fox News debate in Des Moines on Thursday. (Sarah Parnass/The Washington Post)

The first Republican debate without Donald Trump unfolded differently than the others. It was quieter, more cordial — and far more predictable, as the politicians onstage often retreated into talking points and rehashed bits of stump speeches — without a bombastic billionaire to throw them off their game.

The night’s most interesting moments largely revolved around Sen. Ted Cruz, who played the front-runner’s role as Trump boycotted the debate because of a running feud with Fox News Channel, which hosted the event. Rival Sen. Marco Rubio (Fla.) said that Cruz’s campaign was built on a “lie,” because Cruz (Tex.) was not honest about his position changes on the subject of immigration. Sen. Rand Paul (Ky.) said Cruz had an “authenticity problem.”

And Cruz was pressed about an issue where he has been criticized by the popular and long-serving Republican governor of corn-growing Iowa: Cruz’s call to phase out the federal mandate to use ethanol in fuels.

“I don’t believe that Washington should be picking winners and losers. And I believe that there should be no mandates and no subsidies whatsoever” for any kind of fuel, Cruz said. His call for the elimination of the ethanol mandate, which boosts purchase of corn, brought an attack by Iowa’s governor, Terry Branstad.

Cruz sought to reframe his opposition to the ethanol standard as part of a broader rollback of government regulations, which would eventually boost the corn-ethanol industry along with everyone else. He mentioned an even more obscure issue — at least, obscure outside of Iowa — which was the “ethanol blend wall.” That is a limit on the percentage of ethanol that can be blended into fuel, set by the Environmental Protection Agency and supported by oil companies. The logic of the “wall” is that a greater amount of ethanol may harm auto parts. “I will tear down the EPA’s blend wall, which will enable ethanol to expand its market share.”

Trump himself sought to overshadow the entire event, holding a rival event across town meant to honor veterans. He also dominated the news during the debate, after Fox News charged that Trump had asked for a $5 million donation to his charities in return for his appearance at the debate.

Late Thursday evening, Trump responded with a statement that didn’t specifically deny he had asked Fox News for what the network called a “quid pro quo.”

“The event tonight, which raised more than $6 million dollars, and in many respects turned out to be bigger than the debate, was for the Veterans. If FOX wanted to join in that effort and make a contribution Mr. Trump would have welcomed that,” the statement said, in part. It concluded by saying that “Mr. Trump won tonight as well,” even without showing up.

It was unclear whether Trump’s boycott will actually pay off: That may have to wait until Monday, when Iowans finally go to the caucuses.

Ted Cruz and Marco Rubio talk after Thursday night’s debate in Des Moines. (Chris Carlson/AP)

But his absence showed the rest of the GOP field what their race might have been like, without this bombastic and unexpected outsider. For one thing, there was a lot more of what politicians call “pivoting”: taking a dangerous, difficult question, and responding with a safe, poll-tested answer. Asked about their own issues, candidates turned quickly to subjects they all agreed on: The Islamic State must be defeated. Democratic front-runner Hillary Clinton cannot be trusted.

“One of her very first acts as president may be to pardon herself,” Rubio said.

“The days of the Clintons in public housing are over,” said New Jersey Gov. Chris Christie. Those got good laughs, but they did little to differentiate those candidates in a crowded field of candidates, all chasing Trump.

One of the most memorable statements of the night came from retired neurosurgeon Ben Carson, who had been a largely quiet presence. Carson was asked for a closing statement. He responded by reciting the Preamble to the Constitution, one of the most beautiful and succinct explanations of what America is about.

“Folks, it’s not too late,” Carson said after that. “Enough said.”