[mpyne]

Well it would be the USPS, not the NSA, and the USPS does indeed scan today every single mail item they process for "metadata" about the contents of the envelope [1] (note how the linked article reinforces my point about Fourth Amendment protection).

Either way if the failure of the Fourth Amendment to be protective enough is that bad then the solution is either to pass a law adding the needed protection (what Congress did for landline wiretaps) or to wait for an activist judge to quote James Madison in a ruling that expands the permit of the Fourth Amendment (e.g. the ruling today).

But simply wishing that the Fourth Amendment says something other than what it does, doesn't turn the Fourth Amendment into what you wish.

[1] http://gizmodo.com/5994922/how-the-post-office-sniffs-out-an...