ST. PAUL, Minn.—Seeking to have his guilty plea in a bathroom sex sting erased, attorneys for Idaho Sen. Larry Craig argue in a new court filing that the underlying act wasn’t criminal because it didn’t involve multiple victims.

An appeals brief filed Jan. 8 contends that Minnesota’s disorderly conduct law “requires that the conduct at issue have a tendency to alarm or anger ‘others’”—underscoring the plural nature of the term.

Craig’s brief goes on to cite other convictions that were overturned because the multiple-victim test wasn’t met. His lawyers apply the same logic to his case.

The Republican senator pleaded guilty in August after his arrest two months earlier at the Minneapolis airport. It was part of a broader undercover push targeting men soliciting sex in public restrooms.

“Appellant’s alleged conduct in this case affected only a single individual—(police) Sergeant Karsnia,” the Craig brief says. The brief also argues that Karsnia himself could not have been offended by the alleged conduct because “he invited it.” The alleged conduct, Craig’s lawyers added, doesn’t rise to the level of being “offensive, obscene, abusive, boisterous or noisy.”