Craig did not return a message left at his lobbying firm.
The case stems from the Idaho Republican's embarrassing 2007 arrest by an undercover cop in a Minneapolis-St. Paul International Airport bathroom stall. The cop said Craig made sexual advances toward him by tapping his feet under the stall divider.
The senator quietly pleaded guilty to misdemeanor disorderly conduct three months later. But after his case hit the media, Craig reversed himself and hired a team of attorneys to get his guilty plea thrown out.
On Monday, the FEC alleged that Craig used campaign donations from supporters as his own personal piggy bank to to try to reverse his plea. The commission said he paid $139,952 to the Washington, D.C. law firm of Sutherland, Asbill & Brennan and another $77,032 to the Minneapolis firm of Kelly & Jacobson.
"These legal costs were not made in connection with his campaign for federal office or for any ordinary and necessary expenses incurred in his connection with his duties as Senator," FEC lawyers wrote in the lawsuit.
The commission also named Kaye O'Riordan, Craig's campaign treasurer, as a defendant. Craig finished out his term and retired from the Senate in January 2009, but his campaign committee remains.