SAN DIEGO — The wife of U.S. Rep. Duncan Hunter is planning to change her not-guilty plea in a federal corruption case alleging the couple spent more than $250,000 in campaign funds on vacations and other personal expenses, setting up the possibility she will testify against her husband, a close ally of President Donald Trump.

Margaret Hunter, who was her husband's campaign manager, was scheduled to appear Thursday in federal court in San Diego to change her plea.

The congressman's attorney, Gregory Vega, told the San Diego Union-Tribune that Margaret Hunter's decision should have no impact on his client's case.

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Former federal prosecutor Jason A. Forge disagrees. Forge prosecuted California Rep. Randy "Duke" Cunningham, who resigned from Congress in 2005 and served more than seven years in prison for one of the worst bribery scandals to ever bring down a federal lawmaker.

Forge said it's rare for one spouse to plead out when the other's case has not been resolved.

"I would say it's a virtual certainty that she's cooperating with the government and therefore will be testifying against her husband," Forge said, adding he believes that makes the case "winnable."

Forge said Margaret Hunter may be ready to testify about the status of their marriage and how much sway she had over the spending.

Her lawyers did not respond to a request by The Associated Press seeking comment, nor did attorneys for the six-term congressman.

Hunter has said his wife oversaw their finances. Since the indictment last year, the couple have entered federal court in San Diego separately with their own attorneys and also have left separately.

"She can remove any doubt that he might have been able to raise as far as him being away in Washington and that she was 100 percent responsible for all of this activity," Forge said.

The couple, who have three children, pleaded not guilty last year after a federal grand jury indicted them on charges of dipping into campaign cash to bankroll trips to Italy and Hawaii, golf outings, school tuition, theater tickets and other personal expenses between 2009 and 2016.

They also are accused of trying to conceal the illegal spending in federal campaign finance reports. Duncan Hunter's lawyers said in 2017 that the couple repaid the campaign about $60,000.

Hunter was one of two Republican federal lawmakers to win re-election last November after being indicted on corruption charges. He is scheduled to go on trial in September, and his lawyers have called the allegations a political witch hunt.

Vega, his lawyer, wrote in an August letter to the Justice Department urging prosecutors to delay any action until after the election that "while there may be evidence of infidelity, irresponsibility, or alcohol dependence, the underlying facts do not equate to criminal activity."

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The Marine combat veteran was one of the first GOP lawmakers to support Trump before his election. He recently championed dismissal of a war crimes case against a decorated Navy SEAL, which the president has considered.

Special Operations Chief Edward Gallagher is charged with stabbing to death a teenage Islamic State fighter under his care in Iraq in 2017 and then holding his reenlistment ceremony with the body.

Hunter has acknowledged taking a photo with a dead combatant during his time in Iraq.

The Hunter family is a household name in the 50th District that covers largely inland areas of San Diego County and runs into Riverside County. His father, also named Duncan, served nearly three decades in one of the most Republican congressional districts in Southern California.