Metadata is the real data
You can encrypt all you like.  It won't help.<p>Suppose you encrypt all your SMTP/SUBMIT traffic.  If your upstream is a commercial provider, then they will be subject to subpoenas.  If you run your own upstream, then watching who it connects to will often be sufficient to gather metadata of interest.<p>Consider TLS.  Before you can use it you must have used DNS.  Today all DNS resolution goes in the clear.  So game over right there.  Eventually your client's DNS communication with a shared recursive resolver will not be in the clear, but the operator of that resolver will be subject to subpoenas, so game still over.  Let's say we did deploy DJB's encrypted DNS solution.  Well, you can still see which domains people are talking to, roughly, at least as long as they don't share nameservers, and if they do...  You can see where this is going.  Now let's say you did get DNS resolution securely anyways, well, now you have to connect to some IP address, and if it's not hosting many services, then game over, and if it is hosting many services, then SNI will be game over anyways (TLS 1.3 requires SNI).  SNI cannot be encrypted.<p>The problem really is that metadata can't really be encrypted.<p>Mind you, criminals are defeated by data encryption -- mostly anyways.<p>And forcing governments to use subpoenas does mean increasing the cost of metadata gathering.  Plus there won't be infinite retention requirements, perhaps.  So, encryption does help somewhat, which means we must do it -- it's just not a complete solution.