Plan R is an emergency war plan in which a lower-echelon commander may order nuclear retaliation after a sneak attack if the normal chain of command has been disrupted.
15 seconds sound clip from the Dr. Strangelove movie soundboard.
You can hear this line at 00:26:08 in the Blu-ray version of the movie.
Quote context
[...]
- Uh, that's right, sir. You are the only person authorized to do so.
- It certainly does, far beyond the point I would have imagined possible.
- Well, perhaps you're forgetting the provisions of Plan sir.
- Plan R?
- You approved it, sir. You must remember.
- The idea was for Plan R to be a sort of retaliatory safeguard.
[...]