WASHINGTON (AP) – Idaho Sen. Larry Craig defiantly vowed to serve his full term in office on Thursday despite losing a court attempt to rescind his guilty plea in a men’s room sex sting.

“I have seen that it is possible for me to work here effectively,” Craig said in a written statement certain to disappoint fellow Republicans who have long urged him to step down.

Craig had earlier announced he would resign his seat by Sept. 30, but had wavered when he went to court in hopes of withdrawing his plea.

The third-term lawmaker issued his statement not long after Idaho Gov. C.L. “Butch” Otter relayed word he has selected a replacement for Craig in the event of a resignation.

“He is ready to act should we receive a letter of resignation,” said Jon Hanian, Otter’s spokesperson in Boise, in what seemed like a calculated signal that home-state Republicans want Craig to surrender the seat he has held for 17 years.

In his statement, Craig said he will not run for a new term next year.

But in the meantime, he said: “I will continue my effort to clear my name in the Senate Ethics Committee – something that is not possible if I am not serving in the Senate.”

The ethics committee has already signaled it is reviewing the facts of Craig’s case, taking the step after the Senate Republican leadership requested it.

Craig’s decision to stay and fight raises the strong possibility of public hearings – virtually certain to be televised live – centered on the issue of gay sex.

When the charges first surfaced, Craig said he would resign by Sept. 30. But then he decided to attempt withdrawing a written guilty plea in August to a misdemeanor charge of disorderly conduct. He said he would stay in office at least until a judge ruled on that bid.

“Because the defendant’s plea was accurate, voluntary and intelligent, and because the conviction is supported by the evidence ... the defendant’s motion to withdraw his guilty plea is denied,” Hennepin County Judge Charles Porter wrote.

Craig’s lawyer, Billy Martin issued a statement saying his client was considering whether to appeal the ruling.

“We are, of course, disappointed with the ruling issued today,” Martin said in his statement. “Senator Larry Craig maintains that he is innocent and there is insufficient evidence to support a finding that he is guilty. Thus, we renew our arguments that it is manifestly unjust to deny Senator Craig’s request to withdraw his guilty plea. Senator Craig continues his steadfast denial that any inappropriate behavior took place at the airport.

“He is currently considering whether to appeal this decision. Throughout this trying time, Senator Craig has remained a dedicated public servant and continues to serve the people of Idaho with honor and distinction, as he has done for the past 27 years,” Martin said.

Craig shocked the Senate in late August when it was disclosed that he had quietly pleaded guilty to a charge of disorderly conduct after being arrested by an undercover police officer.

The officer said Craig had exhibited behavior consistent with seeking a sexual encounter in a men’s room at the Minneapolis airport.

Craig said he had panicked when arrested, and admitted guilt because an Idaho newspaper had been aggressively investigating allegations that he was gay.

Emphatically denying that was the case, Craig hired lawyers and announced plans to seek the withdrawal of the plea.

“I am extremely disappointed with the ruling issued today,” he said in his written statement. “I am innocent of the charges against me.”

Craig added that over five terms in the House and three in the Senate, “I have accumulated seniority and important committee assignments that are valuable to Idaho.”

He did not mention that at the request of the leadership, he relinquished the senior Republican posts on his committees.

Craig says his actions in the Minneapolis-St. Paul International Airport bathroom June 11 were misconstrued by the police officer who arrested him.

The officer said Craig had looked into his bathroom stall, and tapped his foot and moved his hand under the divider in a way that suggested he was looking for a sexual partner.

Craig denied that in an interview with the officer after his arrest. But he pleaded guilty on Aug. 8. He later said he “panicked” in entering his plea, believing that it would keep the matter quiet. The Idaho Statesman had been holding back an article on rumors about his sexuality, and Craig said in court papers that he feared the arrest would trigger the story.

Porter rejected that as a good reason to withdraw the plea. Any pressure Craig was under “was entirely perceived by the defendant and was not a result of any action by the police, the prosecutor, or the court,” he said.

Minnesota law allows a plea to be withdrawn if a “manifest injustice” occurs, but leaves it to judges to define that. Porter ruled that none occurred in Craig’s case.

“It is not a manifest injustice to force the defendant to be bound by his plea bargain and the waivers and admissions which he made in conjunction with the execution of that bargain,” Porter wrote.

He also wrote that Craig hadn’t produced any “newly discovered evidence” that would clear him.

Sen. Mike Crapo, R-Idaho, Craig’s closest ally in the Senate, said Craig “has the right to pursue his legal options as does any citizen, and I support his effort. I look forward to serving with him as we continue to work on issues important to Idaho.”