MINNEAPOLIS — Senator Craig of Idaho pleaded guilty this month to misdemeanor disorderly conduct after being arrested at the Minneapolis airport.

A Hennepin County court docket showed Mr. Craig pleading guilty to the disorderly conduct charge August 8, with the court dismissing a charge of gross misdemeanor interference to privacy.

The court docket said the Republican senator paid $575 in fines and fees.

He was put on unsupervised probation for a year. A sentence of 10 days in the county workhouse was stayed.

Roll Call, a Capitol Hill newspaper, which first reported the case, said on its Web site yesterday that Mr. Craig was arrested June 11 by a plainclothes officer investigating complaints of lewd conduct in a men’s restroom at the airport.

Mr. Craig said in a statement issued by his office that he was not involved in any inappropriate conduct.

“At the time of this incident, I complained to the police that they were misconstruing my actions,” he said. “I should have had the advice of counsel in resolving this matter. In hindsight, I should not have pled guilty. I was trying to handle this matter myself quickly and expeditiously.”

Mr. Craig, 62, is married and in his third term in the Senate. He is up for re-election next year. He was a member of the House for 10 years before winning election to the Senate in 1990.

He has been one of Republican presidential candidate Mitt Romney’s top Senate supporters, serving as a Senate liaison for the campaign since February.

As word spread of Mr. Craig’s guilty plea, a Romney campaign spokesman, Matt Rhoades, said in a statement: “Senator Craig has stepped down from his role with the campaign. He did not want to be a distraction and we accept his decision.”

Sidney Smith, a Craig aide in Boise, said yesterday afternoon that the senator was “in the [Boise] area” but was declining to give interviews.

Minneapolis airport police declined to provide a copy of the arrest report after business hours yesterday.

Roll Call, citing the report, said Sergeant Dave Karsnia made the arrest after an encounter in which he was seated in a stall next to a stall occupied by Mr. Craig. Sergeant Karsnia described Mr. Craig tapping his foot, which Sergeant Karsnia said he “recognized as a signal used by persons wishing to engage in lewd conduct.”

Roll Call quoted the August 8 police report as saying that Mr. Craig had handed the arresting officer a business card that identified him as a member of the Senate.

“What do you think about that?” Mr. Craig is alleged to have said, according to the report.

Last fall, Mr. Craig called allegations from a gay-rights activist that he’s had homosexual relationships “completely ridiculous.”

Mike Rogers, who bills himself as a gay activist Web logger, published the allegations on his Web site, www.blogactive.com, in October 2006.

Mr. Craig hasn’t said if he plans to run for a fourth term in 2008. An announcement was expected this fall. His spokesman, Mr. Smith, was uncertain if Mr. Craig’s guilty plea would affect his re-election plans.

“It’s too early to talk about anything about that,” Mr. Smith told the Associated Press.

J. Kirk Sullivan, chairman of the Idaho Republican Party, declined to comment on the situation, saying he was unaware of the nature of the charges against Mr. Craig.