Sen. Tom Carper, a Delaware Democrat, admitted to slapping his first wife in a 1998 interview, which was unearthed by the Washington Free Beacon on Thursday.

'Did I slap my wife 20 years ago? Yes,' Carper said. 'Do I regret it? Yes. Would I do it again? No,' the longtime First State politician told Delaware reporter Celia Cohen, who included the admission in her book 'Only in Delaware,' which is sold on the state's official website.

Carper was initially outed for the transgression against his now ex-wife Diane, a former Miss Delaware he had married in 1978, by the New York Post in 1982, as he was running for his first Congressional term.

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Sen. Tom Carper (left), a Delaware Democrat, admitted to a reporter in 1998 that he had slapped his first wife over the course of their custody dispute

Back then, he said the accusation from the tabloid was 'without basis in fact' and pledged to sue the newspaper for libel.

Post reporters had gotten their hands on a 1981 taped deposition recorded as part of a custody battle between the couple over their two children.

The newspaper wrote that during the custody battle, Carper allegedly hit his wife 'so hard he gave her a black eye.'

The Post's story also said the children told the News Journal 'that they were slapped around and bruised by Carper for doing such things as leaving the family dog on the bed.'

At the time, Carper's campaign told the New York City paper that its report was 'totally false.'

The warring couple eventually settled out of course and so the taped deposition was never submitted as an official court record, making it easier for Carper to deny the claims.

A year later, as the allegations were made public, the former couple put on a united front.

'Let me state, unequivocally, that I would never allow my children or myself to be abused,' she told the News Journal in 1982. 'The very notion that anyone would imply such a thing for political gain or any other reason is appalling.'

Carper was actually aided by the publicity, able to attack his Republican opponent Tom Evans by suggesting he had placed the story in the Post, labeling it a 'vicious' effort to 'smear' him and his wife, the Washington Free Beacon pointed out.

In her book, Cohen noted how the abuse allegations had come up twice during Carper's political career, rearing their head again when he was running for re-election as the state's governor in 1996.

Carper went on to serve as a U.S. senator for the state starting in 2001.

'Although public opinion [during the election] swayed Carper's way, the incident was perhaps the lowest in his public life,' Cohen said in her book. 'He would not speak of the allegations, even when they were repackaged and resurfaced 14 years later while he was running for a second term as governor.'

Two years later, however, he told the reporter what he had done.

'In an interview in 1998 for this writing, however, he dealt with them straightforwardly,' Cohen said.

Diane Carper passed away in 2013.

The senator married his current wife, Martha, in 1985 and the couple have two children together.

The second Mrs. Carper was forced to put out a statement saying, 'I love my husband and he loves me,' the Free Beacon noted, after reports that there were marital issues.

The Washington Free Beacon's report comes at a watershed moment for members of Congress as four lawmakers have resigned in the past week for various misdeeds against women.

Carper's Senate office did not respond to a request for comment from the publication.