The comments, made on the debut night of conservative media host Laura Ingraham's show on Fox News, came after Kelly was asked about the recent decision by a Virginia church to remove plaques that honored the Confederate general and George Washington.

"I would tell you that Robert E. Lee was an honorable man," Kelly told Ingraham. "He was a man that gave up his country to fight for his state, which 150 years ago was more important than country. It was always loyalty to state first back in those days. Now it's different today. But the lack of an ability to compromise led to the Civil War, and men and women of good faith on both sides made their stand where their conscience had them make their stand."

The comments came in the midst of an interview that touched on a wide range of topics including the indictments in the Mueller investigation, the United States' relationship with China, and Kelly's work as the secretary of the Department of Homeland Security.

Long seen as a force of order and discipline in the White House, the former Marine general became part of the controversy over the president's calls to Gold Star families this month when he defended Trump's statements to a widow, made false claims about a Florida congresswoman who had criticized the White House and said he would only take questions from reporters who knew families who had lost soldiers overseas. He told Ingraham on Monday that he didn't believe he had anything to apologize for.

On Ingraham's show, Kelly made the comments as part of a larger point about history as it is seen through a modern lens.

"I think we make a mistake, though, and as a society and certainly as, as individuals, when we take what is today accepted as right and wrong and go back 100, 200, 300 years or more and say what those, you know, what Christopher Columbus did was wrong," he said. "You know, 500 years later, it's inconceivable to me that you would take what we think now and apply it back then."

The comments quickly touched off a cascade of strong reactions among progressives on social media.

"Chief of Staff John Kelly's comments are wrong," tweeted Color of Change, a nonprofit that focuses on racial injustice. "There is no compromise between slavery and freedom."

Renato Mariotti, a former federal prosecutor running for attorney general as a Democrat in Illinois, tweeted that Kelly was "half-right."

"The civil war was caused by an unwillingness to compromise. . .over slavery," he wrote.

The country's Civil War history has reemerged as a particularly potent and emotional fight, exploding into full view in August after a weekend of white nationalist rallies in Charlottesville protesting the planned removal of a Robert E. Lee statue devolved into violence. Trump's comments on the rally brought the simmering racial tensions to a fore when he said that there were "very fine people" on all sides of the debate. Of the push to take down the statue, he said, "You're changing history; you're changing culture."

Many cities and states have begun debating how to address the Confederate statues that dot the South, with many choosing to remove the monuments. But the issue has taken an increasingly political turn since Charlottesville, emerging as an attack line in the gubernatorial race in Virginia.

Some polls have shown that the public is divided about the statues and what they represent. About 54 percent of Americans viewed the statues as symbols of Southern pride and not white supremacy, according to a poll from the Economist and YouGov this summer.

While some contend that the Civil War was fought over states' rights, scholars generally agree that slavery was the primary driver of the conflict.