I think the strategy of 'By the time I met her she was so messed up it didn't matter what I did to her' has the possibility of backfiring quite spectacularly.
It certainly doesn't make Andrew's actions look any better to me anyway.
I don't think that is the way it will be put! This would imply Windsor knew something of her background. I hate to disillusion you, but guys do not take a detailed psychological and social history from casual pick ups at a club which are likely to be one night stands.
If the scenario is as reported she was told to "Do to him what you do to Epstein", she would be coming on to him at Tramps (a club), due diligence by him would be checking she was over the age of consent (in the UK). We are talking about the twenty first century, with sexually empowered women, there is no expectation that a man you meet at a club will marry you if he has sex with you (Four Weddings and a Funeral is not what real life in London was like!).
The sex has to be criminal for the case to go forward. It may be sufficient to claim it was criminal because she was subject to trafficking. It may not be necessary to show Windsor committed a crime. Indeed in a somewhat similar instance in the Maxwell trial the judge ruled that sex with a seventeen year old in London was not illicit because she was above the age of consent in London. What I do not know is whether in New York having sex with someone over the age of consent who expressed a desire to have sex with you would be a crime because someone else paid them to have sex with you and trafficked them for the purpose of having sex. Clearly the trafficker is guilty of a crime but is the 'unwitting' sex partner also guilty?
In the UK, there is a separation between proving liability and apportioning damages assuming something similar in the US. The argument that Giuffre had suffered harm prior to meeting Windsor will only happen once he has been found liable for damages and the question become not what you are but how much you charge.
Giuffre is the one who has to claim that sex with Andrew caused her harm. She is the one who will have describe the harm she suffered from him, she is the one who will need to put a monetary cost on the harm.
The defence will be nice and sympathetic, 'Mrs Giuffre suffered a terrible life, sexually abused from age seven by multiple men, this abuse from young childhood has left deep scars. We all sympathise and feel for her. But the jury are asked to do a difficult task, they have to apportion harm. How much harm was done by ten years of abuse prior to Mrs. Giuffre meeting our client, how much by the continued sexual exploitation for the next three years after meeting our client? How much by the episode when our client met Mrs. Giuffre? This is a difficult and heart rending choice members of the jury but justice calls for you to attribute to our client only the harm caused by our clients actions. However sympathetic we feel for the terrible suffering she suffered as a child it is not the responsibility of our client to compensate for harm caused by others. Indeed Mrs. Giuffre has been compensated for the harm she suffered over so many years at the hands of Epstein, and Maxwell. Epstein and Maxwell those evil people who were convicted have rightly compensated Mrs Giuffre for their actions.
We all admire how she has married and had a long and happy marriage with a beautiful family and a beautiful $millions house. It was only right that Epstein and Maxwell compensated her for the harm done by them to her. It was evil and a tragedy how having moved on from being the girl friend of one convicted sex trafficker she fell into working for another. How she was so corrupted that she went out and brought back young teenagers for Epstein and took money for doing so. How she was sent out to seduce people of power and influence and was paid for doing so. She was corrupted by those evil people into participating in their evil acts. We have heard how she boasted of how she succeeded in having sex with a Prince, having be sent out to seduce him. So members of the jury you have to be clear minded and analytic you must judge how much harm did Mrs. Giuffre suffer when she was sent out to seduce our client?