I think he, like Obama, had some other issues that precluded them from rising to the occasion and making the decision the circumstances required. For Obama -- to be partisan and not care what people thought of him, for Comey -- to go with his instinct and not comment, not caring what people thought of him.
But the folks at DOJ and the FBI knew that Comey cared a LOT about what people thought of him. And they used it to their advantage.
After Hillary lost, Bill Clinton summed up what many Democrats and even some Republicans still believe: James Comey cost her the election.
Just days before her defeat,
an open letter circulated among former federal prosecutors and Justice Department officials accusing Comey of unprecedented actions that had left them astonished and perplexedas well as angry. In our network, we are sad, says the former Southern District attorney. He was an American hero. Now who knows how he will go down in history?
https://www.vanityfair.com/news/2017/02/james-comey-fbi-director-letter
So Comey's colleagues circulated this very mean letter about Comey and I think Comey felt some kind of way about it. And he came out kicked the floor out from under Clinton's campaign. He incorrectly assumed she could take the hit. But he should have known that she had already taken DOZENS and would not be able to survive more.
I think the book serves as an honest, accurate contemporaneous account of events as he experienced them and, as such, it is useful.
You are right -- we must get to the voting booths and not take any election for granted.