photo by: Associated Press

Kansas Gov. Jeff Colyer and Kansas Secretary of State Kris Kobach are pictured in this file photo from June 23, 2018, in Salina, Kan. (AP Photo/John Hanna)

OVERLAND PARK — The last party-sponsored debate between GOP candidates for Kansas governor grew heated as Secretary of State Kris Kobach and Gov. Jeff Colyer spent much of the evening criticizing each other and audience members frequently booed.

The debate Thursday night at Johnson County Community College highlighted how the campaign between the two leading candidates has become increasingly bitter with the primary less than a month away, The Kansas City Star reported .

Colyer focused on Kobach’s performance in a federal court lawsuit where he sought to defend previous proof-of-citizenship requirements for voters. U.S. District Judge Julie Robinson ruled last month that Kansas cannot require documentary proof of U.S. citizenship to register to vote and struck down the law, which Kobach had championed. She also found Kobach in contempt of court for not complying with previous orders. He was fined $1,000 last year and faces more sanctions, including being required to attend classes on legal procedure.

“Integrity is an issue for Republicans and there is only one candidate on this stage who has been fined by a federal judge for lying,” Colyer said as Kobach’s supporters booed.

Kobach defended the law during his opening statement but didn’t mention it had been found to be unconstitutional.

During his closing statement, Kobach said he would be more than just “a steady hand on the tiller” in defending conservative social values.

“We’re going to have to fight for our values. We’re going to have to fight like a third monkey trying to get on Noah’s Ark. You understand me?” he said.

The two also sparred over an art display at the University of Kansas that included an altered U.S. flag, The Topeka Capital-Journal reported . Colyer and Kobach had both demanded that the display be taken down and it was eventually moved from an outside exhibit to inside the Spencer Museum of Art.

“I was appalled to see this happen,” Colyer, who called the university’s chancellor Wednesday to ask that the display be taken down.

Kobach noted he demanded that the display be taken down four hours before Colyer did and said the compromise to move it was not enough.

“You don’t want a governor who declares a symbolic victory,” Kobach said.

The two other GOP candidates, Insurance Commissioner Ken Selzer and Patrick Kucera, a Johnson County businessman and preacher, offered more low-key perspective during the debate.

At one point, Selzer walked to the front of the stage, smiled and said, “I hope you see me as a calm and sensible business person.”

“If this is what politics is, it makes me want to jump off the stage,” quipped Kucera, a Johnson County businessman and preacher mounting a long-shot bid for the nomination.

Despite the testiness of the debate, all the candidates pledged to support the eventual winner of the August GOP primary.