How hard is it to say you reject the aims, objectives and endorsement of the Ku Klux Klan? That's the question both pundits and the public are asking after GOP frontrunner for president Donald Trump's shocking appearance on CNN on Sunday.

Trump was asked point blank by anchor Jake Tapper whether he would disavow David Duke, the white nationalist and former Grand Wizard of the Ku Klux Klan, and the other white supremacist groups that are enthusiastically supporting his campaign.

“I don't know anything about what you're even talking about with white supremacy or white supremacists,” Trump replied. “So I don't know. I don't know – did he endorse me, or what's going on? Because I know nothing about David Duke; I know nothing about white supremacists.”

Trump was asked three times on Sunday whether he'd distance himself from the Ku Klux Klan but he refused to mention the group in his answers.

On Monday, hoping to get ahead of the roiling controversy, Trump blamed a “lousy earpiece” for not knowing who David Duke was during the CNN interview.

But as John King on CNN mentioned the earpiece worked fine for other interviews he did on the same morning.

It looks like it was a deliberate dog whistle to people in the South where Trump needs to win on Super Tuesday. If so it was a dreadful stereotyping of whites in the south who have overwhelmingly moved on from the Ku Klux Klan.

For good measure, at the weekend Trump threw in a quote from Mussolini, the fascist dictator of Italy during the Second World War, in his twitter feed.

There is nothing casual about these comments – they are clearly aimed at a key demographic group that Trump wants to win over.

It was pathetic to see Bill O'Reilly defending Trump's comments on Monday night and seemingly encouraging him to change the first amendment and making it easier to sue.

O'Reilly, of course, blamed the media for jumping on Trump. The media did not issue a statement saying it had no position on the KKK.

Explaining his support for Trump in a Facebook post over the weekend Duke wrote: “I think he deserves a close look by those who believe the era of political correctness needs to come to an end,” adding that white nationalists should look for a leader who would secure the border and dismantle the “Jewish controlled” financial industry.

Later on Sunday, evidence was produced that Trump had in fact expressed strong disapproval of Duke in the past. Back in 2000, after deciding not to pursue a presidential bid with the Reform Party, he wrote a strong repudiation of Duke's views.

“The Reform Party now includes a Klansman, Mr. Duke, a neo-Nazi, Mr. Buchanan, and a communist, Ms. Fulani,” Trump said in a statement at the time, referring to arch conservative Pat Buchanan and Lenora Fulani, an advocate of Marxist-Leninist politics. “This is not company I wish to keep.”

But during the interview on Sunday, when Trump was asked repeatedly if he'd distance himself from Duke and other white supremacist groups, he hedged instead, saying he knew nothing about their support for his bid for the GOP presidential nomination.

“I have to look at the group. I mean, I don't know what group you're talking about,” Trump said. “You wouldn't want me to condemn a group that I know nothing about. I'd have to look. If you would send me a list of the groups, I will do research on them and certainly I would disavow if I thought there was something wrong. You may have groups in there that are totally fine – it would be very unfair. So give me a list of the groups and I'll let you know.”

Tapper replied: “OK. I'm just talking about David Duke and the Ku Klux Klan here, but –”

Trump interjected: “Honestly, I don't know David Duke. I don't believe I've ever met him. I'm pretty sure I didn't meet him. And I just don't know anything about him.”

Trump's comments were made two days before twelve states – mostly Southern ones – vote on Super Tuesday. If he defeats Senators Ted Cruz and Marco Rubio in all or most of those states, he will become a near lock for the 2016 Republican nomination.

Rubio quickly slammed Trump for his comments on Sunday. “We cannot be the party that nominates someone who refuses to condemn white supremacists and the Ku Klux Klan,” he said. “By the way, not only is that wrong, it makes him unelectable. How are we going to grow our party with a nominee that refuses to condemn the Ku Klux Klan? Don't tell me he doesn't know what the Ku Klux Klan is. This is serious.”

Cruz tweeted on Sunday: “Really sad. Donald Trump you're better than this. We should all agree, racism is wrong, KKK is abhorrent.”

At a campaign stop in Massachusetts on Sunday, GOP presidential hopeful John Kasich called Trump's comments “just horrific.”

“We don't have any place for white supremacists in the United States of America and he really needs to make his position clear and he ought to do it quickly,” Kasich said.

On NBC’s "Today Show" on Monday, Trump clarified that he does know who Duke is, but he insisted he has never met him.

Trump explained that he didn’t know which white-supremacist groups Tapper was asking him about on CNN. On Sunday, however, he refused several opportunities to denounce any racist groups supporting him.