The Vox reporters account is relative because it shows Reade escalating the story and escalating her search for news media attention.
I'm not sure that escalating the claim signifies that the claim is false. It seems that a common reaction for victims of abuse is to downplay the severity of the abuse, at least at first. People don't always act optimally, especially regarding stressful, painful, or humiliating experiences and memories. A rape victim who initially tries to thread the needle between getting help and minimizing the need for help, and then later decides they need to be more open about how bad it really was, seems entirely plausible to me.
Likewise seeking more media attention. There was no #metoo in the 90s. Or in the 2000s. There was no Social Media brigade ready to take up arms in your cause if you went public. Seeking media attention for rape accusations against a US Senator was a lot more of a crapshoot back then.
It's only very recently that our society has started sending strong signals that going public, and going big, are good strategies for getting justice for sexual abuse. (Of course this can backfire. Our society is also sending strong signals that going public is still a good way to get wrecked, not a good way to be made whole again.)
So, again, a rape victim who initially tries to get help without going public, and later decides they need to go public to get help, also seems entirely plausible to me.
The argument, "there's very little evidence, and what little there is happens to be circumstantial and inconclusive, so maybe it didn't happen" is a good argument in my opinion.
The argument, "she initially described a more minor offense, and didn't go to the press right away, so maybe it didn't happen" seems more like victim-blaming to me, than like a good argument.
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I think the main problem is twofold:
One, rape accusations by their nature are very hard to prove to anyone's satisfaction. The act doesn't always produce a lot of physical evidence or eyewitnesses, and victims are understandably reticent about coming forward promptly with a strong case.
Two, as a society we're trying to have it both ways: We want to believe rape accusations even without good evidence, because we recognize that there are real victims out there, who shouldn't be dismissed just because the nature of the crime means they can't possibly prove their victimhood to the legal standard. But we also want to protect people from false accusations. So on the one hand, we have "believe all women". On the other, we have "innocent until proven guilty".
And we're telling rape victims to come out under the banner of "Believe All Women", and press for justice on that basis. But we don't actually guarantee that any such victim will be welcomed or supported under that banner. Instead you end up with all kinds of weirdness and inconsistency around "I believe all women, but this case is different because reasons."
A related problem is that it's much easier to gain attention through notoriety these days. There are Social Media brigades that will amplify your message to a degree that was impossible twenty years ago. There's a media class that's more than willing to run with any controversial claim, if it drives eyeballs and sells ads.
So if you're a bored fantasist with a bone to pick, it's pretty easy to get national attention by claiming your former boss groped you. Will some people assume it's true? Yes. Will some people assume it's false? Yes. Will some of the same people assume it's true because society needs to treat rape victims better,
and also assume it's false because their guy shouldn't be condemned over unproven allegations? Sadly, yes.