Forty percent of Democratic voters said in a new Hill-HarrisX poll that 2020 candidates should be discussing the business dealings of former Vice President Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE’s son, Hunter Biden.

The survey, released just hours before the fourth Democratic presidential primary debate, found that 64 percent of Republicans also said Hunter Biden’s business ventures in Ukraine should be a campaign focus. Fifty-four percent of independents agreed.

Respondents overall were almost evenly split on the issue.

Fifty-two percent said Hunter Biden’s business dealings in Ukraine should be discussed, while 48 percent said it wasn’t an important campaign issue.

The survey comes amid increased scrutiny of Hunter Biden’s various business dealings.

In an interview with ABC News that aired Tuesday morning, Hunter Biden said he made a mistake by getting involved with foreign companies before considering the political implications. But he maintained that he did not engage in any wrongdoing.

"I gave a hook to some very unethical people to act in illegal ways to try to do some harm to my father,” he told the network. “That's where I made the mistake.”

Hunter Biden also took aim at President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE and his allies, who have seized on his business dealings to paint the Biden family as corrupt.

“What I regret is not taking into account that there would be a Rudy Giuliani Rudy GiulianiThe Hill's Campaign Report: GOP set to ask SCOTUS to limit mail-in voting CIA found Putin 'probably directing' campaign against Biden: report Democrats fear Russia interference could spoil bid to retake Senate MORE and a president of the United States that would be listening to this ridiculous conspiracy idea,” he said.

The interview came just hours before the fourth Democratic debate in Ohio, where Joe Biden will take center stage.

Biden's fellow White House hopefuls have largely avoided speaking critically about Hunter Biden.

"Mr. President, telling lies about Joe Biden won't protect you from the truth," Sen. Kamala Harris Kamala HarrisTexas Democratic official urges Biden to visit state: 'I thought he had his own plane' The Hill's Campaign Report: Biden on Trump: 'He'll leave' l GOP laywers brush off Trump's election remarks l Obama's endorsements A game theorist's advice to President Trump on filling the Supreme Court seat MORE (D-Calif.) tweeted earlier this month. "Joe has more patriotism in his pinky finger than you'll ever have."

The Hill-HarrisX survey was conducted online among 1,001 registered voters. The margin of error for the full sampling is plus or minus 3.1 percentage points.

—Tess Bonn