Democratic presidential candidate Pete Buttigieg warns that racial hostility in America "will reach a boiling point" if policies don't change.

The South Bend, Indiana, mayor, in Iowa for a two-day visit to highlight a new policy focused on protecting workers, spoke of his fears Saturday while meeting with the Des Moines Register editorial board.

“I think that polite opinion in white America is very much behind the reality of what people are putting up with right now in this country. And it will reach a boiling point … I can feel it," Buttigieg said.

Buttigieg said some South Bend residents have disliked his talk about policing issues "because they don’t trust anything that anybody says to them anymore, even when we’re doing the right thing. That could blow this country up."

Buttigieg was alluding to the South Bend community's response in the weeks after the fatal June shooting of Eric Logan, a black man. The white officer who shot Logan did not have his body camera turned on.

The shooting put a spotlight on Buttigieg's relationship with African Americans.

At the editorial board meeting, Buttigieg spoke of the dangers of white supremacy by noting that the Civil War is the closest the country has come to "the American Project ending."

"White supremacy is the force that has come closest to bringing this country to its knees and, I believe, that lurking danger is still with us," he said. "It’s been brought to the surface a little more than usual under this presidency, but it’s always been there, and if we don’t tackle it, even with some challenging conversations about what we all owe each other as Americans, it’s just going to keep secreting this poison into American life."

Buttigieg released a policy proposal this month, called "The Douglass Plan", he says is aimed at addressing "systemic racism." In it, he proposes spending more on health care, education and economic development to help African Americans and all Americans. The plan also includes the creation of a federal database on the use of force by police that could be used to make police more accountable.

Buttigieg highlighted the plan during a visit to Waterloo, Iowa, earlier in July.

Barbara Rodriguez covers the Iowa Statehouse and politics for the Register. She can be reached by email at bcrodriguez@registermedia.com or by phone at 515-284-8011. Follow her on Twitter @bcrodriguez.