I think he has backed himself into a really tight corner. So I'd say pretty stupid.
1) The complainant was photographed as she entered the alleged crime scene and the photos show pre-existing scraps and bruises. She was dishevelled. 2) If she was intoxicated, it may be that she remembers being raped but it could have been at a previous location, and she was being deposited with the Dule party as she became more conscious. 3) If this goes to trial, the complaonant will have to take the stand, and she will be cross examined on where she was when she recieved the pre-existing scrapes and bruises. She will also have to explain her disheveled appearance and disorientation as she entered the Duke party. 4) Upon seeing her disheveled appearance and injuries, the Duke crowd likely insulted her and the two left, only to be invited back. 5) There is conflicting evidence on what happened at the Duke party on the dancers re-entry. If she was raped at the Duke house, it may be the second occasion she had been assaulted that night. It is also possible that she might have been so intoxicated upon arriving at the Duke party, that she had previously fallen down and scraped herself up. This is a tough case for the prosecution: a) They have no DNA evidence from an identified suspect b) they have prexisting injuries of the complainant caused by a fall or a pre-existing assault c) They have a possible pre-existing intoxication of the complainant, which was not established one way or the other at the hospital? d) they have to put the complainant on the stand and subject her to cross examination on a), b) ,and c) above If they have no new evidence and if the trial is a jury trial, there is a good possibility that any accused will be found not guilty. There is also a possibility that the case will be thrown out at the preliminary hearing. Positive identification of the perpetrator(s) may be impossible in this case.
The defense can make a good case for the fact that she had been raped prior to arriving at the Duke party, and that her memory was confused because she had been "a priori" traumatized and intoxicated.
If I was prosecuting this case, without any new evidence, I would have to allow the investigation to continue before bringing the case forward to a grand jury.