ok, first off, the title is slightly misleading, because I'm still not sure, and some is definitely still protected, but it's a bit unclear, and I feel like it's vague enough that a corrupt postal inspector would use one as an excuse.
Resource 1 - Postal Inspector's Site
- Can Postal Inspectors open mail if they feel it may contain something illegal? First-Class letters and parcels are protected against search and seizure under the Fourth Amendment to the Constitution, and, as such, cannot be opened without a search warrant. If there is probable cause to believe the contents of a First-Class letter or parcel violate federal law, Postal Inspectors can obtain a search warrant to open the mailpiece. Other classes of mail do not contain private correspondence, and therefore may be opened without a warrant.
This is the one that has me worried. This means they can't open first class or parcels. However, priority mail envelopes don't fall under either of those categories, and priority mail envelopes probably consist of 80-90% of the USPS drug traffic. So a postal inspector could use this as their reason for not getting a warrant. Dunno if it's valid or not necessarily, but it's there.
Resource 2 - USPS FAQ
Below list the classes of mail which are closed against postal inspection (the Postal Service™ will not open these items to check to see if the proper price has been paid):
- First-Class Mail® items.
- Priority Mail® items.
- Priority Mail Express™ items.
It doesn't matter much. The warrant is super easy to get.....