Ghomeshi, the former host of CBC Radio's cultural affairs show "Q," faces four counts of sexual assault and one count of overcoming resistance by choking at his judge-alone trial.
The alleged offences date as far back as 2002, and legal experts say the passing of time often poses a significant challenge to winning a conviction in such cases.
"The obvious answer is just the degradation of evidence," said Karen Bellehumeur, a former Crown prosecutor who dealt frequently with sexual assault cases. "Not only has the memory of the survivor of the abuse degraded so that peripheral details are not as clear, but also there is no longer the corroborating evidence to be investigated by police."
Jian Ghomeshi leaves College Park Court after his appearance Jan. 8, 2015. (David Cooper/Toronto Star via Getty Images)
Such evidence could include DNA, observations about injuries or damaged clothing, and witnesses, Bellehumeur said, noting that with little physical evidence, such cases typically boil down to a "he said, she said" scenario, especially when the accused and complainants know each other. The issue of consent in those cases, she said, becomes a key element.
"The main problem is that when you have a case that's just one word against the other, which tends to happen more in historic cases...then a criminal case has just such a high standard of proof that it becomes very difficult," Bellehumeur said. "Unless there's a real disparity between the believability of the complainant over the accused then it's going to be very difficult for the Crown to prove a case beyond a reasonable doubt."
"The main problem is that when you have a case that's just one word against the other."
One positive aspect of dated sexual assault cases, however, is that the announcement of charges against an accused can prompt other complainants to come forward, which in turn can help the prosecution, Bellehumeur added.
Complainants who take the witness stand, however, will be grilled by the defence who will be seeking to punch holes in their story.
"The complainant's credibility really stands and falls on her testimony, her demeanour," said University of Ottawa law professor Carissima Mathen. "Because the defendant has very strong rights to present a full defence, it can become difficult."
Pre-trial accounts of alleged offences — as is the case with one of the complainants in the Ghomeshi trial who alleged the broadcaster choked her to the point where she couldn't breathe — are also open to scrutiny.
And even with plenty of testimony, sexual assault cases can often still fall short of convictions due to a lack of definitive evidence to show a crime occurred, Mathen said.
Jian Ghomeshi attends his pre-trial hearing at Old City Hall court in Toronto. The disgraced former CBC radio host plead not guilty to sex assault and choking charges and elected to be tried by a judge alone. (Melissa Renwick/Toronto Star via Getty Images)
"You can have the complainants be sexually assaulted in the sense that she has experienced a violation, and yet the accused is found not guilty because he didn't appreciate that fact," she said.
It's not that Canadian sexual assault laws are lacking, said one law professor, noting that on paper, they are among the best in the world.
"There are two problems with Canadian sexual assault law — one is proof beyond a reasonable doubt and that's not going to change," said University of Manitoba law professor Karen Busby. "The other problem is continuing reluctance of some judges to resist the law reform efforts made in the 90s."
Those reform efforts included changing the definition of consent in sexual assault cases so that consent has to be "contemporaneous and continuous," as well as changes on the use of personal records and past sexual history in such cases, said Busby.
Some judges, however, still fall back on sexual stereotypes, said Busby, citing the recent case of an Alberta judge who suggested to a complainant that she ought to have kept her knees together, prompting a formal complaint.
"As long as judges are willing to disbelieve women and continue to rely on sexual stereotypes, cases that in my view should be open-and-shut cases, won't be."
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