Carelessness with classified material does not require intent.
Obama is a political a$$, but that is not a revelation.
Woodward is deliberately soft-shoeing this issue, IMO. He, too, is a political a$$.
The 800 pound Gorilla in all this is if the investigation of the email legitimately led them to discover acts of bribery, etc, involving the Clinton Global Initiative.
The results of that avenue of investigation would not be “Fruit of the Tainted Tree.” In fact, it would be evidence discovered “in plain sight” while conducting another legitimate investigation.