Same for Hillary. Her big challengers will be from the lunatic fringe part of the dem party (warren, sanders).
IMO, the presidental nomination will come down to two things. First, will the independents and everyone else on the fence overlook Hillarys emails, Benghazi, and whatever else pops up? Secondly can Bush take Florida? If he can, he'd have a shot. If Bush can't take Florida, Hillary wins.
Emails and benghazi are non issues as far as election day is concerned. These are things the media drives down throats because there's nothing else to cover but your average voter could care less about Benghazi or deleted emails.