(CNN) -- The Minnesota Court of Appeals on Tuesday rejected U.S. Sen. Larry Craig's effort to withdraw his guilty plea to a misdemeanor offense of disorderly conduct in connection with a sex-sting operation.
Sen. Larry Craig, pictured here in August, says he was the victim of police entrapment.
"Because we see no abuse of discretion in the denial and conclude that the statute is not overbroad, we affirm" a lower court's decision, the three-judge panel wrote in a 10-page ruling.
In a written statement, Craig said he was "extremely disappointed" by the action and was considering an appeal.
"I disagree with their conclusion and remain steadfast in my belief that nothing criminal or improper occurred at the Minneapolis airport," Craig said.
The Idaho Republican was arrested in the Minneapolis-St. Paul airport in June 2007 after an undercover police officer accused him of soliciting sex by using hand signals and tapping his foot in a bathroom stall. Two months after his arrest, and without consulting a lawyer, Craig pleaded guilty to the charge without appearing in court.
After the incident became public, he attempted to withdraw his plea, contending that his "wide stance" had been misinterpreted by the arresting officer and that he had pleaded guilty simply to get the matter over with.
In an effort to persuade the panel to throw out Craig's guilty plea, his attorney argued that Craig's foot tapping was protected by his First Amendment right to freedom of speech.
But the judges were unpersuaded.
"A government may constitutionally prohibit such speech if there is 'a showing that substantial privacy interests are being invaded in an essentially intolerable manner.' " they said, citing a previous case.
"Offensive speech may be prohibited as intrusive when the 'captive' audience cannot avoid the speech. ... A person using a restroom stall is such a 'captive' audience with substantial privacy interests that would be intolerably invaded even by communications less potentially offensive than sexual solicitations.
"Thus, even if appellant's foot-tapping and the movement of his foot towards the undercover officer's stall are considered 'speech,' they would be intrusive speech directed at a captive audience, and the government may prohibit them."
Craig's lawyer, Billy Martin, had also argued before the panel that no one besides the arresting officer saw the hand signals and foot tapping, which would mean no one else was offended by the behavior, invalidating the disorderly conduct charge.
But the panel wrote that "... a statutory reference to 'others' does not necessarily mandate the presence of more than one person."
And the judges denied Craig's assertion that he was entitled to withdraw his plea because he was the victim of entrapment.
They wrote that "failure to explore an entrapment defense has been found not to justify withdrawal of a guilty plea."
They cited a precedent ruling that said entrapment "exists only where the criminal intent originates in the enforcement officials of the government rather than in the mind of the accused."
Then, they added, "Here, the complaint clearly indicates that the criminal intent originated in the mind of appellant, not in the officer."
In February, the Senate Ethics Committee issued a "letter of admonition" to Craig in connection to the case.
In the letter, the committee accused him of improper conduct and said his actions reflected "discreditably" on the chamber.
The committee also criticized Craig for using more than $200,000 from campaign funds to pay legal fees related to his case and for flashing his Senate business card at the officer who arrested him. The letter said that move could be seen as an improper attempt to receive "special and favorable treatment."
Craig initially said he would resign after the incident was reported in the news media, then decided to remain in the Senate and fight to have his guilty plea thrown out. But the three-term senator did not seek re-election this year and will retire when his term ends in January.