Silver's appeal has rested on his basing things on numbers. He's supposed to have done something that allows him to supersede punditry. I very much agree that there is a lot of misunderstanding of statistics out there, and that doesn't help. But if all he's saying is, "I can never be wrong because I never put 100% or 0% odds on anything," then there's not really much value to his brand of analysis. It really comes down to poll averaging, plus a little bit of incorporation of fundamentals.
You can check how good someone is at assigning probabilities by looking at their overall track record. Do events that they predict to be 80% likely happen 80% of the time? Do the 90% events happen 90% of the time?, etc. But you can't pick out a single one of those events and "prove" that the probability assigned was wrong after the fact, because there's no objective check for such a thing. That doesn't mean that you can't laugh at the assigned probability for being too optimistic or pessimistic, based on the information at hand. But those assessments are subjective. That's not a dodge by Silver. That's just a matter of definition.
I don't have a problem with people laughing at Silver's assessment of the race. I'm just confused about people making things up about what Silver is predicting (suggesting that "this guy isn't going to win the nomination in the end" means "this guy's support is going to evaporate tomorrow"), and then saying that he's already been "proved wrong" on this because of polls with Trump at 30%. And again, this isn't just about Silver, but all of the "party decides" people. They are largely saying that Trump isn't going to win. Not that he's not going to get a lot of votes. Let's wait until the votes are counted before declaring them as having been "proved wrong".
Has anyone ever done so in Silver's case? (I don't know whether his number of predictions are enough to make this statistically significant, but if so, it would be interesting to see). And it would be particularly interesting to see how accurate they are, say, six months before an election and not just the day before.
And though Silver gets plenty of unfair criticism (and I agree with your points here), that is more than outweighed by the large amount of undeserved praise IMO. After all, it is not that much of an exaggeration to say that he was labeled a genius for basically looking at a polling average.
(Of course, Silver's status was somewhat helped by the fact that the vast majority of GOP pundits and "experts" acted like insane morons regarding the 2012 polls. Anyone with a basic understanding of numbers - who was not a deluded hack - would have looked brilliant in comparison to them.)
