SAN DIEGO—U.S. Rep. Duncan Hunter was swarmed by demonstrators yelling “shame on you!” as he left a federal courthouse Thursday in San Diego after pleading not guilty to charges of illegally using his campaign account for personal expenses.

The California Republican and his wife, Margaret, entered their pleas in federal court, where prosecutors said bond could be set low because the couple is living paycheck to paycheck. The judge agreed to set bail at $15,000 for the congressman and at $10,000 for his wife.

After the arraignment, demonstrators holding signs that read “Duncan Hunter Ethics and Integrity Matter” and “Crooked Duncan Hunter” followed him as he walked to a pickup truck. He got in and removed a “Lock me up!” sign shoved onto the windshield as he was driven away. His wife was not seen leaving the courthouse after the arraignment.

A 60-count indictment unsealed Tuesday charges the couple used more than $250,000 to finance family trips to Italy and Hawaii, golf outings, school tuition, theater tickets and even fast food purchases, and then attempted to conceal the illegal spending in federal records.

Even as the five-term incumbent was under investigation by the FBI, Hunter easily won a 30-point victory in a June primary and established himself as a strong favorite to hold onto his strongly Republican 50th Congressional District seat in San Diego and Riverside counties, which his father held for many years.

Hunter’s attorney, Gregory A. Vega, has claimed there was politically motivated pressure to tarnish Hunter before the general election.

Vega told reporters after the arraignment that “the congressman has faced more difficult battles than this in Iraq and Afghanistan. He looks forward to his day in court.” Hunter’s website says he quit his job as a business analyst soon after 9/11 and joined the Marines, serving three combat tours overseas.

In a statement, House Speaker Paul Ryan called the charges “deeply serious” and said Hunter will be removed from his committee assignments, pending resolution of the case. House Democratic leader Nancy Pelosi said Ryan should call on Hunter to resign.

The California secretary of state’s office said there is no process in the elections code for Hunter to remove his name from the ballot, and there can be no write-in candidates for the November election.

The indictment alleges the couple dipped into campaign cash for years to bankroll their lifestyle, while their household budget was awash in red ink. The spending ranged from the banal to the lavish, from movie tickets to a $6,288.74 family vacation at a resort in Hawaii.

“The Hunters spent substantially more than they earned,” the indictment said. “They overdrew their bank account more than 1,100 times in a 7-year period resulting in approximately $37,761 in ‘overdraft’ and ‘insufficient funds’ bank fees.”

Hunter’s opponent in the general election is Ammar Campa-Najjar, 29, a Democrat who has never held elective office. He received 17 percent of the votes in the primary, coming in second to Hunter. The top two vote getters in California primaries advance regardless of their party affiliation.

Campa-Najjar made a brief appearance outside the courthouse before Hunter exited. He promised to bring “national pride” to the district not “national shame.”