Personally I don't think what you will "allow" makes a whole lot of difference. Of course if they do this it must be absolutely secret and with no mistakes. If they get caught, they will be subject to prosecution.
I also think (hope) we will do the same kind of black ops. The next time a shipload of missiles leaves North Korea we should slip a sub next to it in the middle of the night and put SEALs onboard, disable their communications, and sink it. Funny how that ship just disappeared. Just like that ship full of uranium in the 60s that left France for an Arab country and vanished. It's widely believed in intelligence circles that the Mossad hijacked it and the uranium was used to build Israel's nuclear arsenal.
That's the point, they always get caught, their incompetent and can't be trusted. That's just one reason why we limit their power. In a country where the President can't get a hummer in the White House without the whole world knowing about it and high ranking FBI and CIA employees on the KGB parole, just how long would this secret last.
Again I see no legal problems with doing it overseas.