U.S. Rep. Duncan Hunter says he will plead guilty to misusing campaign funds — a criminal case he'd once decried as a politically motivated "witch hunt."

The Republican lawmaker will formally enter his guilty plea in a hearing in federal court in San Diego on Tuesday morning, his court docket shows.

In an interview with KUSI News, Hunter said he would plead guilty to one count of misusing campaign funds in the case.

"I did make mistakes. I did not properly monitor or account for my campaign money," he said. "I am responsible for my campaign and what happens to my campaign money."

The change of plea was first reported by the San Diego Union-Tribune.

Prosecutors had charged Hunter and his wife "converted and stole" more than a quarter million dollars in campaign funds for their own use, including trips to Hawaii and Italy, bar tabs, theater tickets and school tuition for their kids. Prosecutors have also charged that Hunter used campaign money to finance romantic flings with lobbyists and congressional aides.

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Both Hunters pleaded not guilty last year, but the Republican congressman and Iraq war vet appeared to blame his spouse for their problems in an interview on Fox News soon after.

"When I went away to Iraq in 2003, the first time, I gave her power of attorney. She handled my finances throughout my entire military career and that continued on when I got into Congress," Hunter said on "The Story."

"She was also the campaign manager, so whatever she did, that’ll be looked at, too, I'm sure, but I didn't do it."

Hunter's wife, Margaret, pleaded guilty to conspiring to misuse campaign funds in June, and was expected to testify against her husband at his trial, which had been scheduled for Jan. 22.

"I think it's important not to have a public trial for three reasons, and those three reasons are my kids," Duncan Hunter said in the KUSI interview.

He said he did not know how much time he'll get from the judge, but added, "Whatever my time in custody is, I will take that hit. My only hope is the judge does not sentence my wife to jail. I think my kids need a mom at home."

Hunter is a staunch ally of President Donald Trump, and was the second sitting member of Congress to endorse his 2016 presidential campaign.

The first, Rep. Chris Collins of New York, pleaded guilty last month to federal charges related to insider trading and resigned his seat. Like Hunter, he had taken a page from the Trump playbook and said the investigation into his actions was "a political witch hunt."

Hunter, who'd been running for re-election next year, was vague when asked what would happen with his seat.

"We're going to pass it off to whoever takes the seat next. I think it's important to keep the seat a Republican seat," he said. "President Trump right now needs support more than ever."