4.0

This story was told chronologically, from the discovery of America to the publication. I think the Mr. Woodard was very careful - when talking about historical events that come "after" the period he's in at any given moment - about which nations played what roles. He drops phrases like "several of [the nations] have tried to leave the union," but makes you read the book to find out which. It creates a bit of a "dun, dun duuun" moment.