Yeah me too, I mean there are rules about obtaining evidence in a court case and some methods aren't allowed and the resulting evidence is inadmissible no matter how juicy it is.
Is a presidential campaign less critical than a court case? Should there be rules around what is and isn't admissible? Probably no practical way to decide or mediate something like that, everything would become a protracted court case.
So probably nothing you can do about it. I bet information security will become a higher priority for lots of people after this campaign, but maybe it's better if everyone just assumed even their private emails are public and act that way.
EDIT: Though even acting as if your emails are public isn't really a solution, the vast majority of "dirt" dug up in the Podesta emails is simply people not bothering to read or understand the context. I guess my real problem with democracy is people are dumb
