Were she a small-time dealer in a drug bust instead of a left-wing radical in a high-profile bombing case, Sara Jane Olson would have almost no hope of convincing a judge to let her withdraw her guilty pleas, legal experts say. And even with a pack of reporters and a committee of well-organized supporters in tow, her chances remain slim.

"Five percent. There's about a five percent chance," ventured defense lawyer Gary Mandinach, who represents indigent clients with the California Appellate Project in Los Angeles.

"It's a long shot," agreed Loyola Law School professor Laurie Levenson, a former federal prosecutor.

But Olson will make the attempt Monday before Judge Larry Fidler in the same courtroom where she twice pleaded guilty in the 1975 attempted bombing of Los Angeles police cars. Prosecutors have derided Olson's withdrawal attempt as "contrived protestations of innocence voiced after fully informed voluntary pleas of guilt." They say that if she claims to be not guilty under oath Monday they will put her on the stand and cross-examine her about her two previous sworn admissions of guilt before the judge.

Olson is up against California's high standard for allowing defendants to withdraw guilty pleas. Regret or second thoughts are just not enough. There must be proof that a mistake, ignorance, fraud or duress interfered with a voluntary plea. In the rare cases in which defendants have been permitted to withdraw pleas and proceed to trial, there is ample evidence that they did not understand what they were doing or were forced into it.

"We're talking about somebody being brought out of lock-up, sort of stumbling into court, having a lawyer whisper in their ear, 'You're going to plead guilty.' The judge asks them how they plead. The lawyer whispers, 'Guilty.' The client says, 'Guilty.' The judge says, 'Are you sure?' The lawyer whispers 'yes,' and the client says, 'yes,' and that's it," said Ira Reiner, former Los Angeles district attorney. "We're about as far away from that here as you can be."

Olson, 54, acknowledges working closely with her lawyers not just in the weeks leading up to the October 31 plea, but for the two years between her arrest and the start of the trial. Under the deal, Olson could serve as little as five years and as much as a life sentence. In exchange, prosecutors dropped a murder conspiracy charge, which carried a mandatory life term, and agreed not to object to Olson serving her time in Minnesota, rather than California. She said the decision came after intense discussions with her lawyers and soul searching with family and friends.

"I made this decision slowly over a period of time," she told reporters minutes after formally admitting her guilt to Fidler.

And Olson pleaded guilty not once, but twice. When after the first hearing she told the press that she was actually innocent and had only pleaded guilty because of the political climate created by the September 11 attacks, the judge hauled her back into court and made her reiterate her guilt. At that hearing, a week after the first, she denied ever planting bombs but pleaded guilty "under the concept of aiding and abetting."

"Because you are in fact guilty," Fidler pressed.

"Yes," Olson said.

Just six days later, however, Olson signed an affidavit asking Fidler to withdraw her plea. In it, she wrote that "cowardice" led her to strike the deal and that she had since found "the courage to take what I know is the honest course."

"After deeper reflection I realize I cannot plead guilty when I know I am not," Olson wrote.

Some suspected that the affidavit, short on legal grounds and long on emotion, was a face-saving gesture by Olson for leftist groups who had labeled her a "political prisoner" and taken up her banner of innocence. But a second affidavit, filed by defense attorney J. Tony Serra, left little doubt that Olson was making a serious attempt to go to trial.

Serra wrote that he had urged her to plead guilty because he thought prosecutors would only push for a three-year sentence and because he felt the "surge of patriotism" since September 11 would increase the chances for a conspiracy conviction.

"I, in part, take responsibility for creating conditions in her mind that amounted to psychological duress in regard to pleading guilty," he wrote, adding that his client was in "psychological condition of coercion" during the plea.

By using the legal buzzwords "coercion" and "duress," Serra gave Olson's request some legal ground.

While successful withdrawals are extremely rare, when they do occur they often rest on a defendant's misunderstanding of the terms of his sentence. Judges have granted withdrawals, for example, in cases where an immigrant defendant was not told deportation would be a result of a guilty plea.

Although Serra said prosecutors led him to believe they only desired a three-year prison term, in court, Fidler repeatedly told Olson it would be up to a parole board to determine where her sentence fell in the five-years-to-life range.

From defense affidavits, it seems clear Olson plans to focus her arguments on coercion, a much murkier area than misunderstanding a sentence. Courts have allowed defendants to take back pleas if they were coerced by a third party or convinced to take a plea because of fabricated evidence.

In the Los Angeles Police Department's Rampart scandal, Fidler freed inmates who had pleaded guilty to crimes they did not commit. The defendants had made the pleas because they faced long prison sentences and knew that corrupt officers were prepared to offer false testimony at a trial. But in cases where the coercion was not as egregious, many judges have refused to grant a withdrawal.

In a notorious California federal case, Unabomber Ted Kaczynski failed in his attempt to withdraw his guilty plea for three mail-bomb murders. He argued that his defense team had forced him into a plea by planning an insanity defense over his objections. The effect, he said, was coercive, and he demanded a trial, with Serra as his attorney. A federal appeals court found no coercion, however, just legal advice that likely saved Kaczynski from the death penalty.

"Coercion is a difficult argument because if you want to get hypertechnical, there is an element of coercion in every plea," said defense lawyer James Epstein, a former public defender in Los Angeles. Lawyers present the facts and the likelihood of conviction, and "sometimes you are coerced by the facts," he said. "Voluntary doesn't mean you want it or you are happy about it. A plea is the lesser of two evils."

To ensure pleas are legitimate, judges question defendants extensively before accepting them, and Judge Fidler oversaw two lengthy voir dires of Olson.

"It was much more thorough in this case [than in an average case] especially the second time around," Mandinach said. "It certainly appears that they tried to cross all the Ts and dot all the Is."

Olson's greatest hope for a trial might stem from the media attention to her case.

"If the judge cares about public confidence in the plea, he might very well permit her to withdraw her plea" said UCLA law professor Peter Arenella. "We don't want the public to doubt the legal process ... because it's such a high-profile case."

Radicals who hoped her trial would disclose government abuses against the counterculture in the 1970s might make her "some kind of martyr," said defense lawyer Harland Braun. "It might end up bringing disrepute on the system."