IMHO what Nate Silver does is not a prediction on the outcome of future events, such that when he doesn't get it right it is because he has failed, but rather a

IMHO what Nate Silver does is not a prediction on the outcome of future events, such that when he doesn't get it right it is because he has failed, but rather an analysis of existing data in order to provide a detailed description of our own uncertainty. And by seeing how this uncertainty evolves as more data comes in or different events happen, we get a better understanding of the underlaying process.