I’ll try to condense this to explain an interesting wrinkle. Every few years the President of the United States would approve a National Security Council scenario of the likeliest threats to the United States and the military response to them. This wasn’t done in a vacuum. The Secretary of State and the Secretary of Defense would articulate some overarching concept such as “containment” or “massive retaliation” or “flexible response” and point the Joint Chiefs towards that policy. Eisenhower, for one, didn’t want to run around the world meeting the Soviets wherever they choose to be bad guys — it was too expensive and kept a conflict on their terms — so he took a new look and came up with “massive retaliation” — we’re going to respond when and where we want with everything we ‘ve got.
That political decision then became the basis of the Emergency War Plan which, in this case, was embodied in NSC 68, which called for massive retaliation. From NSC 68, the individual Joint Chiefs would send their planners into action to create the Emergency War Plans for, say the Air Force or the Navy. This ultimately filtered down to the wing level where a wing-level Emergency War Plan was created and practiced.
Here’s the neat wrinkle. I’ve read this about a dozen times but it didn’t sink in until I interviewed a B-36 crew member from those years. There was a problem with the word “plan.” It seems “plan” connoted a thought or an idea and not an action so they changed it; they changed the Emergency War Plan to the EWO — the Emergency War Order. Problem solved.