“his model” meaning Silver’s model? That sounds like it might be right. I think another commenter here correctly identified that it’s a misunderstanding -- Sil

“his model” meaning Silver’s model? That sounds like it might be right. I think another commenter here correctly identified that it’s a misunderstanding -- Silver’s model estimates “the election result of the election were to happen tomorrow”, so unlikely events in the coming months don’t need to be accounted for by definition. If so, I think there’s a valid criticism that the “now-cast” notion is a bit deceptive, and also impossible to validate (we’ll never know what that hypothetical election result would actually have been).