Cosby was the first celebrity to go on trial in the #MeToo era, and his appeal could resolve lingering questions about how the cases should be tried.
For starters, the high court will try to clarify when other accusers can testify against a defendant — and when the additional testimony amounts to character assassination.
In a brief filed in Cosby’s appeal, public defenders in Philadelphia noted courts had given conflicting guidance on the issue.
“Courts repeatedly fail to analyse how uncharged misconduct is relevant to prove, for example, intent or identity,” the Defender Association of Philadelphia wrote in the brief, one of several filed in the case in the past month.
They say the testimony should only be allowed if it is linked to a single crime scheme, to avoid “the genuine risk that defendants will be convicted for who they are, or for what they may or may not have done before”.
Prosecutors, in a brief filed on Monday, offered several legal justifications for the accusers’ testimony, hoping at least one of them would stick. They said it was needed to show Cosby’s pattern of behaviour, to show the encounter was not a one-time mistake, and to show the complaint was not filed on a whim.
“It is unusual, to say the least, that defendant has been repeatedly … accused of engaging in sexual conduct with unconscious or otherwise incapacitated young women … without any consequences,” the Montgomery County District Attorney’s Office wrote in their response to Cosby’s appeal.
Cosby, 83, will mark two years in prison this month and has another year left before he can seek parole.
However, he has vowed to serve the full 10-year maximum rather than show remorse for what he calls a consensual 2004 encounter with Andrea Constand, a former professional basketball player who worked for the college he attended, Temple University, in Philadelphia.
Cosby won a chance to reverse his conviction earlier this year, when the state Supreme Court agreed to review two central trial issues: the other accuser testimony and Cosby’s claim that a former prosecutor had promised he could never be charged in the case.
Cosby’s lawyers said they relied on that promise when they let him testify in a civil suit that Ms Constand filed in 2005, soon after the suburban Philadelphia prosecutor declined to arrest the former TV star.
A successor, Montgomery County District Attorney Kevin Steele, arrested Cosby a decade later after the comedian’s damaging deposition from the lawsuit was unsealed.
The Pennsylvania Attorney General’s Office, in a brief in support of Mr Steele, said the Cosby camp’s decision to rely on an unwritten promise before he testified in such “a grave matter … was unreasonable”.
The Supreme Court has not yet set a date for oral arguments. Other groups filing legal briefs in the appeal include the Rape, Abuse & Incest National Network, known as RAINN; the Pennsylvania Association of Criminal Defence Lawyers; and the Pennsylvania District Attorneys Association.
Cosby was convicted of three counts of felony sexual assault based on charges he drugged and molested Ms Constand after she went to his house for career advice.
The five other accusers who testified for the prosecution said they believed he also drugged and sexually assaulted them in the 1980s.
