Refuse to confirm or deny could have helped the US in 1960:
An American U2 "weather research" plane is shot down over the USSR.
The US strongly denied that the U2 was a spy plane and produced "weather research" U2s in NASA livery and a story about how the pilot's oxygen equipment malfunctioned.
...the USSR had failed to mention that the U2 pilot (Gary Powers) was alive and well, and that the definitely-a-spy-plane was recovered mostly intact. Oops!
An American U2 "weather research" plane is shot down over the USSR.
The US strongly denied that the U2 was a spy plane and produced "weather research" U2s in NASA livery and a story about how the pilot's oxygen equipment malfunctioned.
...the USSR had failed to mention that the U2 pilot (Gary Powers) was alive and well, and that the definitely-a-spy-plane was recovered mostly intact. Oops!