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

An appeals brief filed Tuesday 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.

Craig was arrested June 11 by an undercover officer, Sgt. Dave Karsnia, who said Craig tapped his feet and swiped his hand under a stall divider in a way that signaled he wanted sex. Craig has denied that, saying his actions were misconstrued.

"Appellant's alleged conduct in this case affected only a single individual — Sergeant Karsnia," the Craig brief says. "It did not — and could not affect 'others' as the disorderly conduct statute requires, and therefore, does not satisfy that element of the statute."

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."

Craig's earlier attempt to withdraw his plea was turned down by a district court judge, and the case is now before the Minnesota Court of Appeals.

Besides attacking the law he was prosecuted under, Craig's legal team argues that the hand signal allegedly used to communicate a desire to engage in sexual conduct would be constitutionally protected speech. They also say the plea is technically flawed because it lacked a judicial signature.

Patrick Hogan, a spokesman for the Metropolitan Airports Commission, which oversees the Minneapolis airport and which brought the charges, said he was confident the guilty plea will stand.

"Facts are resilient, and Sen. Craig's continued, transparent efforts to escape them don't change the truth of his behavior in an airport restroom or the fact that he admitted guilt last August," Hogan said.

Prosecutors have 45 days to respond, and then the case will be scheduled for oral arguments. Once heard, a ruling is required within 90 days.

Craig has said he will finish his term, which ends in January 2009.