ST. PAUL, Minnesota (Reuters) - Lawyers for U.S. Sen. Larry Craig of Idaho asked a Minnesota Court on Wednesday to void the guilty plea he made following his arrest last year in a men’s toilet sex-sting operation.

U.S. Senator Larry Craig (R-Idaho), (R), before the start of the presentation ceremony of the 2007 National Medal of Arts and the National Humanities Medals from U.S. President George W. Bush in the East Room of the White House in Washington, November 15, 2007. REUTERS/Larry Downing

The three-term Republican, who is retiring when his term ends in January, did not give up his legal rights by pleading guilty to disorderly conduct, a misdemeanor processed by mail much the same way as a traffic ticket is, said William Martin, Craig’s lawyer.

The complaint against Craig, he told the Minnesota Court of Appeals, was not sufficient to prove his guilt.

But prosecutor Christopher Renz argued in response that the complaint plus Craig’s guilty plea was sufficient to end the matter, and that he would have pleaded guilty had he appeared in person for a hearing. He urged the court not to let Craig take back his plea.

Craig was arrested at Minneapolis-St. Paul International Airport on June 11, 2007, after an undercover police officer said the lawmaker kept looking through a crack in the door, sat down in a stall next to him and used hand and foot signals to indicate he was soliciting sex.

Craig said his actions were misread, that he was not gay, and that he panicked and pleaded guilty to the charge. He at first said he would resign but then decided to serve the balance of his term. He is likely to be replaced by another Republican in the November election.

During Wednesday’s oral arguments, which lasted less than an hour, Martin said Craig was only looking into the stall to see if it was occupied.

“But the police officer could see that his eyes were blue,” responded Judge Natalie Hudson. “He was peering in the crack.”

“Your honor,” replied Martin, “you’re guessing. You shouldn’t have to guess on appeal.”

Hudson and two other judges on the panel who heard the arguments took the case under advisement and will issue a ruling in several weeks. Craig did not attend the hearing.