
Let’s be very clear about what the NSA said in its statement. It denied “targeting” Carlson, but did not deny reading his emails. The NSA also did not deny that it may have accessed Carlson’s communications through “incidental collection.”
These were huge omissions, since incidental collection is a well-known and controversial way the NSA collects vast amounts of Americans’ communications without warrants. This happens when an innocent American communicates with a legitimate NSA target, such as someone believed to be under the control of or to be collaborating with a hostile foreign power.
When this happens, the name of the innocent American is supposed to be “redacted” or masked. There are very strict rules on how incidentally collected communications of U.S citizens can be used.