These weren’t just ordinary secrets found in Clinton’s private server, but some of the most classified material the U.S. government has.
Most seriously, the Inspector General assessed that Clinton’s emails included information that was highly classified—yet mislabeled as unclassified. Worse, the information in question should have been classified up to the level of “TOP SECRET//SI//TK//NOFORN,” according to the Inspector General’s report.
You may have seen acronym lists like these on declassified documents before—and glazed over them. This is the arcane language of the cleared cognoscenti so let me explain what this means:
• TOP SECRET, as the name implies, is the highest official classification level in the U.S. government, defined as information whose unauthorized release “could cause exceptionally grave damage to national security or foreign relations.”
• SI refers to Special Intelligence, meaning it is information derived from intercepted communications, which is the business of the National Security Agency, America’s single biggest source of intelligence. They’re the guys who eavesdrop on phone calls, map who’s calling who, and comb through emails. SI is a subset of what the intelligence community calls Sensitive Compartmented Information or SCI. And these materials always require special handling and protection. They are to be kept in a Sensitive Compartmented Information Facility or SCIF, which is a special hardened room that is safe from both physical and electronic intrusion.
• TK refers to Talent Keyhole, which is an IC caveat indicating that the classified material was obtained via satellite.
• NOFORN, as the name implies, means that the materials can only be shown to Americans, not to foreigners.
In short: Information at the “TOP SECRET//SI//TK//NOFORN” level is considered exceptionally highly classified and must be handled with great care under penalty of serious consequences for mishandling. Every person who is cleared and “read on” for access to such information signs reams of paperwork and receives detailed training about how it is to be handled, no exceptions—and what the consequences will be if the rules are not followed.