There really should be no expectation of privacy in e-mail.

Who are you to decide that? Like I said in a post on a similar topic:

"...the canonical user interface icon for e-mail is... a sealed envelope. Even ISPs will present their e-mail services with such an image.

In other words, the snagging point is the definition of "expectation of privacy" -- but the situation is really quite simple: The average user simply expects privacy, but the government is trying to force them to abandon that expectation, so they can then go and install ubiquitous e-mail surveillance without violating the letter of the US Constitution. The government is trying to win by arguing semantics, so what I find hardest to believe is that anyone is taking all this blatant skullduggery seriously.

... It's not like mailing a postcard, it's like sending an electrically encoded text message over a packet-switched data network where the only expected viewing point is at the intended recipient's terminal; this is how the e-mail protocol was designed to work. Sure, a malicious party can read it because it's not encrypted, but someone can easily slice open a postal mail envelope and read the contents of that, too.

The bottom line is, since a non-trivial effort has to be made to read the contents, and since the service has always been presented as a "sealed letter", the average user is not unreasonable in expecting privacy."