Using the example of General Petraeus, the Electronic Frontier Foundation explains how the federal government looks at private email.  What can be done about these abuses?

[The Electronic Communications Privacy Act (ECPA (1986)] is hopelessly out of date, and fails to provide the protections we need in a modern era. Your email privacy should be simple: it should receive the same protection the Fourth Amendment provides for your home. So why hasn’t Congress done anything to update the law? They’ve tried a few times but the bills haven’t gone anywhere. That’s why [Electronic Frontier Foundation] members across the country are joining with other advocacy groups in calling for reform. This week, we’re proud to launch a new campaign page to advocate for ECPA reform.