Former Sen. Larry E. Craig, R-Idaho, may face an uphill battle trying to convince a federal judge that he properly used campaign funds to pay for his legal defense after being arrested for soliciting sex in an airport bathroom.

U.S. District Court Judge Amy Berman Jackson, in a hearing Monday in Washington, D.C., likened it to using official re-election funds to pay for being arrested for robbing an airport kiosk or propositioning a prostitute, according to a report from The Associated Press.

Craig was arrested for lewd conduct in July 2007 at the Minneapolis-St. Paul International Airport after allegedly soliciting sex in an airport bathroom. Craig tapped his foot inside his stall to indicate to other restroom patrons that he was seeking sex, according to a law enforcement officer used in the sting. Craig pleaded guilty to a lesser charge of disorderly conduct the next month.

After Roll Call broke the news of Craig’s arrest and guilty plea in early August, the senator announced that he would resign. He later decided to stay in the Senate but not seek re-election when his term ended.

Ethics rules and laws allow lawmakers to use campaign funds to defray the cost of legal battles if the case relates to the official duties they perform as public servants. Craig used more than $217,000 from his re-election account, even though his lawyers told the Senate Ethics Committee that the airport sex sting was “purely personal,” The Associated Press noted.

“I’m supposed to ignore that?” Jackson asked, according to the report.

The Federal Election Commission has asked the court to force Craig to repay the money to his former campaign.

An earlier version of this story incorrectly stated the timing of Craig’s departure from the Senate. He announced his resignation but later changed his mind, going on to finish his term.