(Reuters) - Bill Cosby's appeal of his conviction for sexual assault is expected to focus on a Pennsylvania judge's decision to allow several accusers to testify against him, but his challenge faces significant hurdles, according to legal experts.
The disgraced comedian's first trial hinged largely on the credibility of a single woman, his one-time friend Andrea Constand, who said he drugged and sexually assaulted her in 2004, and ended in a hung jury.
At his second trial in April, Montgomery County Judge Steven O'Neill allowed the jury to hear five other women with strikingly similar stories of sexual abuse. Cosby was found guilty and on Tuesday was sentenced to up to 10 years in prison.
Cosby's lawyers face a difficult burden in convincing an appellate court to second-guess O'Neill's decision, experts told Reuters.
"I don't think that they have any significant likelihood of winning this appeal," said Michelle Dempsey, a law professor at Villanova University in Philadelphia. "The evidence was solid, and the standard in Pennsylvania is clear."
Other potential appeals grounds include the decade-plus gap between the crime and Cosby's arrest, claims of bias against the trial judge and an alleged promise by a former district attorney not to prosecute Cosby for the Constand incident.
Cosby, once known as "America's Dad" for his role as the beloved patriarch of the Huxtable family on the 1980s television comedy "The Cosby Show," has been accused by more than 50 women of sexual abuse dating back decades. Only Constand's allegations were recent enough to lead to criminal prosecution.
He was given a minimum of three years in prison on Tuesday and immediately taken in handcuffs to the county jail. His lawyers are expected to ask an appellate court to free him on bail while his appeal is pending.
A lawyer and a spokesman for Cosby did not respond to a request for comment on Wednesday.
Typically, testimony about "prior bad acts" is barred from trial, under the theory that jurors may end up convicting the defendant for misconduct unrelated to the crime in question. But many states, including Pennsylvania, permit such witnesses if they are called to show a specific pattern of behavior.
In Cosby's case, virtually all of his accusers have described a similar modus operandi. He offered some form of mentorship before plying them with drugs or alcohol in a place he controlled, such as a hotel room or his own home, to facilitate sexual assault.
At Cosby's first trial, prosecutors sought to call more than a dozen other accusers, but O'Neill limited them to just one: Kelly Johnson, who said Cosby drugged and assaulted her in 1996.
Ahead of the second trial, however, O'Neill gave prosecutors permission to call five women as witnesses. He did not offer his legal reasoning, but under Pennsylvania law, he will be required to do so in writing if Cosby's lawyers raise the issue on appeal.
In between the two trials, the #MeToo movement, the national reckoning with sexual misconduct by powerful men, was born following allegations against the movie mogul Harvey Weinstein.
Wesley Oliver, director of the criminal justice program at Duquesne University in Pittsburgh, said the defense would likely question why O'Neill changed his mind.
"If the judge found one to be the appropriate number the first time around, how do you explain five the second time around?" he said in an interview after Cosby's conviction in April. "The law didn't change between these two cases; society changed a lot. If you're the appellate court, what do you do with that?"
The legal standard to reverse O'Neill's decision is whether he abused his discretion, a high bar to clear, according to experts.
Nevertheless, appellate courts tend to look closely at prior bad act witnesses because the potential for prejudice against the defendant is also high, said Dennis McAndrews, a former Pennsylvania prosecutor.
Cosby's lawyers are also likely to renew their argument that former Montgomery County District Attorney Bruce Castor promised Cosby in 2005 he would not be prosecuted if he agreed to sit for a deposition in Constand's civil case against him.
The deposition, in which Cosby acknowledged giving sedatives to young women, was unsealed a decade later, and prosecutors cited it as a crucial piece of evidence when they brought criminal charges.
Even so, legal experts said the lack of a written deal with Castor, as well as the fact that Cosby had his own lawyers at the time, would make it hard for Cosby to argue that he had an ironclad agreement.
In the meantime, his family and aides are pressing his case in the court of public opinion.
Cosby was the subject of "the most racist and sexist trial in the history of the United States," his publicist, Andrew Wyatt, told reporters just minutes after he was led out of the courthouse in shackles on Tuesday.
Reporting by Joseph Ax; Editing by Frank McGurty and Tom Brown