If Petraeus was using his offical email, or even his private email on a government computer, it was all subject to monitoring without any warrant.
Sure they are. Aldritch Ames, Hansen, Manning, et al are proof of that. Good thing these guys were rolled up before they could do any damage.
Valerie Jarret I’m sure has terabytes of sigint proving she as pure as the Sibeian snows.