In both the UK and the US trial, Mr Depp's lawyers argued that Ms Heard was lying - to make their case, they attacked her character and claimed that she was in fact the abusive partner.
This is a common defence tactic in sexual assault and domestic violence trials called "deny, attack, and reverse victim and offender" or "Darvo", said Mr Stephens.
The strategy turns the tables on the alleged victim, shifting the conversation away from "did the accused commit abuse" to "is the alleged victim believable".
"They deny that they did anything, they deny they're the real perpetrator, and they attack the credibility of the individual calling out the abuse, and then reverse the roles of the victim and the offender," Mr Stephens said.
In the UK trial, Mr Stephens said the judge recognised that strategy, and dismissed a lot of the evidence that did not directly address whether Mr Depp committed assault or not.
"Lawyers and judges tend not to fall for it, but it's very, very effective against juries," he said. Men are more likely to believe Darvo arguments, but female jurors are also susceptible.
