So you believe in doing significantly more harm to the victim just so the Mounties can get their Man? My mother was a victim of sexual abuse as a child, and she was horrified when she heard of this case - the idea of some independent "white knight" (very sarcastic quote marks there) forcing her to endure reliving those memories almost made her physically sick.

We're talking about a case that was decades old and whose victim didn't want to go forward. It's not a case that is in any sense 'live'. Child abuse and child sexual abuse is present in every country, in every city. Chasing a 30-year-old crime is pointless feathering of one's own cap - instead those same prosecutors could be out there stopping today's child abusers, and preventing today's children from ongoing abuse. There is so much child abuse out there that planting your flag on any one case and saying "This is the one!" is clearly self-aggrandising.

If you are so horrified by the idea of sexual abuse of children, then why be so cavalier with the idea of making victims relive that horror against their mature, expressed consent?

>>>why be so cavalier with the idea of making victims relive that horror against their mature, expressed consent?

Vacri: your comment seems reasonable and educated so I assume that you know the answer to your own question. I'm answering here so that the other folks reading this will also know the answer. I'm not educated about the specifics of the Roman Polanski case, so this is a general comment about the state prosecuting crimes when the victim would like the crime not to be prosecuted.

>>>why be so cavalier with the idea of making victims relive that horror against their mature, expressed consent?

One possibility is the prosecutor "feathering one's own cap" as you said. Another possibility was hinted at in an earlier comment: "prosecutor is representing the state". Convicting an offender of an old crime has the potential to do good things for society. Two of them are:

Bring forth other victims

Create credibility for the claims of future victims("convicted child rapist raped my child" is more believable than "normal upstanding citizen raped my child")

From my understanding, the reason lies in the theories of "crimes of passion/poor judgement" vs "patterns of behavior". If someone commits a crime by accident or in the heat of the moment then certain actions should be taken to explain to them their mistake(e.g. rehabilitation, imprisonment, therapy, probation). If they make a "pattern of behavior" then society can conclude that society doesn't have the tools to convince the offender to end their pattern of offending, and the offender should be physically disallowed from committing future offenses in their pattern:

bad lawyers are restricted from practicing law - "dis-bar-ment"

offending computer users are restricted from using computers