The Cain camp shouldn’t even dignify this with a reply. Just ignore them and move on. If anyone asks tell them to consider the source and leave it at that.
Depends on what it does to his poll numbers and his fund-raising efforts. And if this story drags on in the media, which it will on PSMNBC and CNN, he may not be able to ignore it. Again, it will take him off message and even though it’s Gloria Allred, it could still cost him.