The two major party candidates for the U.S. Senate disagreed over some familiar issues during their third and final debate in Sioux City tonight, but their argument over who had the “pure heart” of a devoted Christian sparked an intense exchange.

Republican Joni Ernst brought it up first when a debate moderator asked what set her apart from Democrat Bruce Braley.

“Sound bites do have consequences,” Ernst said, repeating a phrase Braley has been using, before continuing, “and I believe that I have a pure heart, willing to serve Iowans, where Congressman Braley behind closed doors has poked fun at our senior senator, Chuck Grassley. I don’t call that building bridges. I call that burning bridges, congressman.”

Braley immediately responded, saying he had apologized to Grassley and to Iowa farmers for his remarks at a Texas fundraiser in which Braley warned that Grassley — a farmer who isn’t a lawyer — would become chairman of the Senate Judiciary Committee if Republicans win the U.S. Senate.

“So if you’re questioning my pure heart, senator, I can tell you that I’ve been an elder in my church. I’ve taught Sunday School to adults and children. I’ve never seen a corporation sitting next to me in the church pew and yet you believe that their interests outweigh those of women in Iowa when it comes to contraception,” Braley said.

Ernst a few minutes earlier had said she agrees with the U.S. Supreme Court ruling which says some family-owned corporations like the Hobby Lobby chain do not have to provide their employees insurance that covers contraception if the family has religious objections.

“But that doesn’t mean a woman can’t get reliable, safe birth control,” Ernst said. “She can still go to her doctor and receive birth control. It’s not outlawing birth control.”

Braley said no business should be able to select the types of contraception their employee insurance plans cover.

“She supports a Supreme Court decision that allows employers to interfere with an individual woman’s health care decisions about her contraception,” Braley said.

During a discussion about taxes, Ernst touched on her support for a “flatter, fairer, simpler” tax, like a national sales tax instead of a federal income tax.

“I say, ‘Scrap the IRS,'” Ernst said. “Let’s start all over again.”

Braley replied.

“Senator Ernst’s answer to everything is: ‘Scrap it.’ Scrap the IRS. Get rid of it. Get rid of the Department of Education. Get rid of the EPA.”

And Ernst responded.

“I don’t believe in a bloated federal bureaucracy,” Ernst said. “We need to return a lot of that power to the states.”

The candidates began the debate by addressing concerns about Ebola and both said it may be necessary to temporarily ban flights into the U.S. from west Africa. Midway through the debate both candidates denounced the negative campaign advertising swamping Iowa’s airwaves. Braley said he supports efforts to reign in the outside spending, but Ernst said they’re “exercising political free speech” and “that’s a right.”

The debate was held at Morningside College in Sioux City and sponsored by TV stations KCAU in Sioux City and WOI in Des Moines.