MINNEAPOLIS — Sen. Larry Craig said he hopes that his guilty plea in an airport sex sting will be rescinded by a court in Minneapolis today.

The first step in the process of wiping away that plea, however, has nothing to do with whether an undercover policeman misunderstood Mr. Craig’s actions in a bathroom stall at the Minneapolis airport. Instead, it’s all about whether Mr. Craig’s attorneys can convince Judge Charles Porter that the Idaho senator’s plea was a mistake.

“He’s already gotten lots of justice and fairness,” a professor in criminal law at Hamline University, Mary Jane Morrison, said. “A court will view this as taking not just a second bite at the apple, but a fourth and fifth bite. Because he had the right to refuse to plead in the first place, and put the state to its proof. He had the right to have an attorney help him figure out what was in his best interest.”

Mr. Craig won’t be attending the hearing, a spokeswoman for Craig attorney Billy Martin, Judy Smith, said. Stopping briefly to speak to reporters as he left his home in the Washington area early today, Mr. Craig said he hoped the judge would “allow me to prove my innocence.”

Mr. Craig has said his foot-tapping, hand gestures, and looks into a bathroom stall were misconstrued by the police officer conducting a sting for bathroom sex at the airport. Mr. Craig’s attorneys wrote that he pleaded guilty to misdemeanor disorderly conduct because he feared his June 11 arrest would trigger a story by an Idaho newspaper that had been investigating his sexual orientation. Mr. Craig has denied that he is gay.

Mr. Craig announced that he intends to resign from the Senate on September 30, but a spokesman has said there is a slight chance he may keep his seat if he can withdraw his plea.

Mr. Craig’s attorneys are trying to prove that letting the senator’s plea stand would be a “manifest injustice.” The term isn’t defined in the law, but is generally left up to judges to determine on a case-by-case basis, legal experts said. If the plea is withdrawn, prosecutors could refile charges.

Mr. Craig’s case should be reopened in part because he never appeared in court before pleading guilty, his attorneys argued.

In plea bargains in open court, judges walk the defendant through testimony about precisely which actions violated the law. Mr. Craig mailed in a written plea agreement that admitted disorderly conduct, but the agreement did not describe exactly what he did that was illegal. Mr. Craig’s attorneys argued that a judge’s inquiries would have prevented Mr. Craig from pleading guilty because it would have become clear that he hadn’t done anything illegal.

A Minneapolis defense attorney, Joe Friedberg, said that argument is a lot better than the one that Mr. Craig was panicked into a guilty plea.

“The only shot he’s got is if the judge determines that there’s no factual basis for the plea,” he said. “I don’t think that a factual basis is set forth in that plea, and I think that it should be voided. None of his stress … makes any difference.”

Ms. Morrison said it’s not uncommon for judges to demand less detail in misdemeanor pleas.

“They’re pretty careful on felony (cases), and they’re not so careful on misdemeanors,” she said.

Indeed, prosecutor Christopher Renz argued in court papers that thousands of guilty pleas are entered the same way.

If Mr. Porter refuses to allow Mr. Craig to withdraw his guilty plea, the senator can take it to the state’s Court of Appeals. Yesterday, that court ruled against a different defendant who wanted to withdraw his guilty plea for criminal sexual conduct because he said he didn’t understand part of his plea.

In that case, the appeals court ruled it was up to the trial court to decide whether to allow pleas to be withdrawn.