That's also a possibility, but she'd have to be some kind of fool to make that claim, knowing she couldn't back it up.
If we assume that she's lying about the tape, then it's probably safe to assume that she's also lying about the abuse, and that Ellison isn't really the monster she's making him out to be. Maybe the whole thing is a political hit job, set up to ruin Ellison's political career.
Does he have enemies on the left that hate him that bad?