Pressure on Sen. Larry Craig continues to mount as the national Republican Party apparatus builds an intense behind-the-scenes effort to suggest and perhaps order a resignation from the embattled Idaho senator.

The Republican National Committee and the White House actively are discussing Craig strategy — debating how much pressure to apply on the senator, who pleaded guilty to a misdemeanor disorderly conduct charge in connection with a police sting operation into lewd conduct at a men's airport restroom in Minnesota.

The rising political pressure for Craig to resign coincides with the release Thursday of the audio tape and transcript of Craig's interview with the undercover police detective who arrested him after the bathroom incident.

In the at-times contentious interview, Craig is given his Miranda rights and he waives his right to be represented by an attorney. He never admits to the police version of the incident. He also explains that he needs to end the interview quickly so he can make a connecting flight, and tells the officer he is not gay.

Click here to read the transcript of the audio interview of Sen. Larry Craig.

Click here to listen to the interview.

Party sources told FOX News that the RNC might publicly call for his resignation Friday. No decision had been reached on that, but the option is being weighed.

Pressure built on Thursday when Nevada Sen. John Ensign said that Craig's guilty plea makes it nearly impossible for him to remain in office. Ensign is in charge of the Republican Senate Campaign Committee, which seeks to put more party members in the Senate. A broader statement by Republican Senate leadership also is being considered, sources say.

Ensign stopped short of calling on the three-term senator to resign his seat, but strongly suggested he do so.

"I wouldn't put myself hopefully in that kind of position, but if I was in a position like that, that's what I would do," Ensign told The Associated Press. "He's going to have to answer that for himself."

Ensign said Craig made his situation more difficult because he "admitted guilt, he pled guilty. It's a little different situation than just being accused of something."

Sen. Norm Coleman, R-Minn., the first senator to call for Craig's resignation on Wednesday, and Sen. Susan Collins both said they will be giving to charity $2,500 donations given to them from Craig. Coleman has said the money will go to Sharing and Caring Hands, a Minneapolis-based charity that helps the poor. The donation came from Craig's political action committee, Alliance for the West.

Other lawmakers who received donations this year from Alliance for the West include Sens. Pete Domenici and John Sununu. All four Republicans have tough re-election battles next year.

Domenici, who is currently in New Mexico, told FOX News early in the day that he does not want to rush to judgment, but "the action being taken by the Senate Republican leadership is a good first step toward getting the facts. It's important that we allow the legal process to run its course and the Senate ethics committee to conduct a thorough and fair investigation."

Domenici's statement is similar to Thursday's on-the-record remarks from the White House.

"The whole matter is one of disappointment and it has been referred to the Senate ethics committee. We really want this to be resolved quickly, that would be in the best interest of the United States Senate and the people of Idaho," said spokeswoman Dana Perino.

Back in Idaho, Craig remains in seclusion, but the winds of change are rustling in his hometown of Boise. Craig's home state newspaper, the Idaho Statesman, called for the senator's resignation in a Thursday editorial.

"It is difficult and unpleasant to call on Idaho's senior senator to end a career in public service. We don't do this casually, or unanimously," the paper's editors wrote.

"However, we cannot abide an elected official who didn't disclose a lewd conduct arrest until the story broke 77 days later — a lie by omission and a violation of the public trust. We cannot believe Craig can effectively serve Idaho, under the shadow of his guilty plea on a lesser charge of disorderly conduct. We cannot afford, as a state with but four congressional representatives, to have a senator who merely provides fodder for bloggers and late-night talk show hosts."

The movement against Craig is part of a concerted effort by Senate Republican leaders, who are trying to learn the lessons of the Mark Foley page scandal and distance themselves swiftly from a colleague ensnared in sexual misconduct.

Several prominent Senate GOP officials told FOX News that Republican leaders don't want to repeat the circular firing squad that engulfed the House GOP leadership last year after evidence surfaced about lewd e-mails from Foley, then a Florida congressman, to a congressional page.

In that case, House GOP leaders fought publicly over who knew what when and how Foley's case should be handled — feuds that deepened the story's corrosive effect on party morale and sparked public doubts about Republican vigilance on ethics and public morality.

There is no evidence yet that Craig's misconduct will cost Republicans the so-called values voters who have formed their base for years. But as one GOP leadership staffer put it, "We were just beginning to make some headway on the Democrats with their bad poll numbers and there was some encouraging news from Iraq and now this. The Craig news sets everything back."

But just as the leadership ramps up its pressure on Craig, it's also leaving room to allow Craig to make a decision on his own. That kind of inaction gives the longtime lawmaker a chance to try to recoup some dignity as he bows out.

If Craig does give up his seat, it will not affect the balance of power in the Senate. Idaho is a very red state. The entire delegation is comprised of Republicans. According to the Idaho secretary of state's office, should Craig step down, Republican Gov. C.L. "Butch" Otter, who has been preoccupied with wildfires in the state, would name an interim replacement to serve until next year's election.

FOX News' Major Garrett contributed to this report.