The cross-examination of complainants in the Jian Ghomeshi trial is a legacy of Canada's legal system that was historically very selective when determining if women alleging sexual assault were worthy of protection, according to a law professor.

Constance Backhouse, who teaches law at the University of Ottawa and is the author of Carnal Crimes: Sexual Assault Law in Canada 1900-1975, told CBC News the Ghomeshi trial has highlighted remnants of a legal system dating back to the 19th century when a woman "had to convince the court that you were blameless."

She said trials would not focus on what the accused had done, but instead on the character of the victim, said Backhouse, who served as panel leader of the task force that published a report on the Dalhousie Dentistry Facebook scandal.

Constance Backhouse, author of Carnal Crimes: Sexual Assault Law in Canada 1900-1975, says the Ghomeshi trial has highlighted an outdated legal system when a woman 'had to convince the court that you were blameless.' (CBC)

"You had to convince them that you were a pure woman, modest, no sexual history or background outside of marriage — preferably a virgin — a high reputation for being moral and pure," she told CBC Radio's Information Morning.

"And if you did anything that besmirched that reputation, all of a sudden you were open season for rapists. There was no criminal law protection."

Hue and cry theory

Another factor was the "hue and cry" theory used to determine whether a woman was a legitimate victim of sexual assault.

The theory, Backhouse explained, suggested that if a woman was really raped, she would raise enough commotion to legitimize the claim.

"She would come screaming from the bushes with her clothes torn off, and she would be dishevelled and injured — and bleeding, preferably — and she would scream about what had happened to her to the very first person she saw," she said.

"And if she didn't raise a hue and cry, that was enough to torpedo the case."

Backhouse said feminist lawyers like her have fought to have laws changed over the last 30 years. They believe that every woman should be free to say yes or no to sex whenever she wants to.

It's about a specific act at a specific time.

'A lesson for us'

Laws have been changed to protect complainants from questions about their sexual history, but that doesn't seem to have made a difference, said Backhouse.

"I guess that was a lesson for us, those of us who laboured to change the law. You can't change the laws ahead of the people," she said.

Most of the legal lessons of rape-shield laws have been ignored because although the law says the victim's behaviour is irrelevant, that's not what our culture thinks, Backhouse said.

"If you examine this [Ghomeshi] trial, basically because the victims gave consent to some things — before, during and after the alleged non-consensual behaviour — we're all making assessments that they are not believable about the non-consensual part.

"And yet if I asked your listeners the question, 'Do you really think that women who are out on a date, however much they are star struck by a celebrity, would consent to being punched, choked … without express consent for that asked ahead of time?' I expect that there, the popular culture is on our side, and that they would say, 'No, I suspect they wouldn't consent to that.'"

Backhouse believes that if either law or society focuses on whether a woman gave consent in the days before or after an alleged sexual assault, "then we're back in the 19th century again."