UPDATE: EFF Applauds New Electronic Privacy Bill That Tells the Government: Come Back With a Warrant!
As the law stands now, the authorities may obtain cloud e-mail without a warrant if it is older than 180 days, thanks to the Electronic Communications Privacy Act adopted in 1986. At that time, e-mail left on a third-party server for six months was considered to be abandoned, and thus enjoyed less privacy protection. However, the law demands warrants for the authorities to seize e-mail from a person’s hard drive.
via Justice Dept. to Congress: Don’t Saddle 4th Amendment on Us | Threat Level | Wired.com.