FVEY is an intelligence cooperation agreement that is invaluable to the security of the world. I don't see how any reasonable person could view it as anything n

FVEY is an intelligence cooperation agreement that is invaluable to the security of the world. I don't see how any reasonable person could view it as anything negative. What exactly is the objection to classifying some information as SECRET//US,UK,CAN,AUS,NZ instead of SECRET//NOFORN ?