U.S. Rep. Duncan Hunter admitted to misusing campaign funds at a hearing in San Diego federal court on Tuesday, bringing an end to his fight against criminal charges that he had claimed were politically motivated.

Prosecutors charged that Hunter and his wife "converted and stole" more than a quarter million dollars in campaign funds for their own use over a period of several years. That included using campaign cash for family trips to Hawaii and Thanksgiving in Italy, plane rides for relatives and his pet rabbit and even $1,500 for video games. Prosecutors said Hunter also used campaign money to finance romantic flings with lobbyists and congressional aides.

"I failed to monitor and account for my campaign spending. I made mistakes, and that's what today was all about," Hunter, 42, told reporters after a brief proceeding in which he withdrew his earlier plea of not guilty and admitted to one count of conspiracy to misuse campaign funds.

In his signed plea agreement, Hunter specifically acknowledged that the "object of the conspiracy was for the Hunters to convert campaign funds for their own personal benefit and enjoyment, and for the personal benefit of others with whom they had personal relationships."

Hunter did not say whether he planned to resign his seat, which he has held since 2008.

"I'll have more statements in the future about the future," he said.

Assistant U.S. Attorney Phil Halpern told reporters that what Hunter pleaded to was "not about mismanagement of his campaign."

"Congressman Hunter himself misappropriated his own campaign funds for the use of himself and his family," he said, adding the couple used the campaign cash "as a piggy bank to float a lifestyle they couldn’t maintain." He said Hunter pleaded guilty to the top count, which "encompasses all of his criminal activity."

Halpern also took aim at Hunter's earlier conspiracy theory.

“No figure, regardless of what office they occupy, should be allowed in this country to cry witch hunt or fake news and attempt to deflect their criminal wrongdoings,” Halpern said.

The prosecutor said he's been told by Hunter's lawyer that he plans to resign the seat, which he'd been running to keep in 2020.

“Rather than reelection, Mr. Hunter now faces resignation, disgrace and imprisonment,” he said.

Hunter, R-Calif., faces up to five years in prison when he is sentenced on March 17. His wife, Margaret, pleaded guilty earlier this year to conspiracy to misuse campaign funds and was expected to testify against her husband of more than 20 years if the case went to trial.

The six-term congressman publicly pointed the finger at his wife after they were indicted last year.

"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 told Fox News after their arrest. "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," he said.

Hunter is a staunch ally of President Donald Trump and was one of the first members 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 echoed Trump's often-stated line about special counsel Robert Mueller's probe in calling the investigation into his actions "a political witch hunt."

Collins is scheduled to be sentenced on Jan. 17. He also faces up to five years in prison on his charges.