Lawyers for former U.S. Sen. Larry Craig filed court papers late last week defending his use of campaign money to pay legal bills related to his 2007 arrest in a Minnesota airport sex sting.

The Federal Election Commission is suing Craig, an Idaho Republican, in federal court in Washington. The FEC claims the $216,984 Craig spent on legal bills in an unsuccessful effort to withdraw his guilty plea wasn’t an “ordinary and necessary” expense related to his official duties as a senator. Craig’s attorneys late Friday defended his use of campaign money, pointing to Senate rules and the commission’s own advisory opinions.