Have we not learned anything in the last 9 years?
E-mails just don’t ‘disappear’ into the ether.
They can be gotten, if you know where to look.
The NSA, National Archives, other places within the FBI IT infrastructure, back-ups of back-ups, etc.
The idea that they are ‘gone’ is ludicrous on its face. Heck, even Wikileaks may have copies and most certainly our enemies................
They all have standard retention periods of at least two years for such items. In some cases they hold them longer.
All it takes is a court order to retrieve them.
Logs of all phone calls are also retained by the phone companies for varying periods of time. There are supposedly records preserved of long-distance calls that date back to the early 1960's or late 1950's.
Most likely the NSA already has a complete collection (illegally) of the "missing" text messages.