Thanks too to NJ for his analysis.
I would say in reply that there are two different aspects of responsibility at play here, and they are often confused particularly in situations like this. But at the heart of any case before the law is the issue of who is criminally responsible, and there can be no doubt that, however questionable some decisions may be, there can be no criminal responsibility involved if you find yourself the victim of a crime. This is true in rape, it is true if your house is burgled, etc etc. Example:
One night, when I was younger, Dad accidentally left the kitchen door open for whatever reason, and someone managed to come in and steal a few things in the hall including my PE kit for the following day. Obviously, it was Dad's mistake to leave the door open. But that doesn't take any responsibility for committing the crime of burglary away from the burglar at all. Whoever it was was never caught, as understandably there was basically no evidence at all. He/ she came into the house and left ten seconds later without being seen.
Responsibility for leaving the door open, then, is certainly Dad's, in part; had the case ever come to court, that would have had not a bit of bearing on the legal crime. The same should be true in cases of rape, in that regardless of any errors in judgement on the part of the victim, they should have no bearing on assessing whether a crime took place or not.
Obviously when it comes to sentencing I'd expect the guidelines to treat more seriously the cases where the woman had consciously refused as opposed to those who'd 'consented' without really being able to, but both crimes are, and should be, prosecuted as rape, and the man in both cases would and should bear the sole legal responsibility for his actions.