Some of you who say my talk at Phreaknic might recall my observation that the 4th Amendment doesn't apply on the Internet. Interestingly enough, an appeals court today decided that it does. The EFF is touting this as a big win. However:

On remand, therefore, the preliminary injunction shall allow seizures of e-mail in three situations: (1) if the government obtains a search warrant under the Fourth Amendment, based on probable cause and in compliance with the particularity requirement; (2) if the government provides notice to the account holder in seeking an SCA order, according him the same judicial review he would be allowed were he to be subpoenaed; or (3) if the government can show specific, articulable facts, demonstrating that an ISP or other entity has complete access to the e-mails in question and that it actually relies on and utilizes this access in the normal course of business, sufficient to establish that the user has waived his expectation of privacy with respect to that entity, in which case compelled disclosure may occur if that entity is afforded notice and an opportunity to be heard.

The later part is the kicker. I think any ISP can show that they use email headers to route messages. In reading the decision this might be insufficient for the judge. In that case it could be quite interesting.

Email 4th Amendment Ruling