The question came up during an interview Sunday on CNN's State of the Union, when host Jake Tapper asked Trump whether he wanted to disavow support from racist organizations, like the KKK. The group's former grand wizard, David Duke, who became a national figure after he ran for governor of Louisiana in 1991, posted on his Facebook page last week he was supporting Trump. Duke called a vote for someone other than Trump "treasonous."
When the topic came up, Trump said he had no knowledge of Duke's support, but failed to distance himself from the white supremacist group, generally.
"I don't know anything about what you're even talking about with white supremacy or white supremacists," he said. "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."
When Tapper mentioned the KKK specifically, Trump implored the host to give him the names of any the groups of questionable origin that are supporting his campaign, pledging he would "research" them and respond later.
In its original statement on the issue, the Anti-Defamation League called Duke's views "bigoted" and demanded Trump say so himself.
"It is time for him to come out firmly against these bigoted views and the people that espouse them," the group's leaders said last week.
Trump's failure to immediately repudiate support from the KKK drew swift and harsh criticism from his rivals for the Republican nomination. Sen. Marco Rubio, of Florida, said Trump's response makes him "unelectable." Texas Sen. Ted Cruz took to Twitter, lecturing Trump, "you're better than this."
After the flare-up, Trump took to Twitter to tamp down the controversy. He posted a video of a press conference two days prior, when he was also asked about Duke's support.
"I didn't even know David Duke endorsed me," Trump said, adding: "I disavow, OK?"
The questions carried over into Monday, when Trump appeared on NBC's Today show. Trump defended his response on CNN the day before, saying he didn't hear Tapper correctly during the satellite interview because his ear piece malfunctioned.