I suspect the US Joint Chiefs didn't foresee their involvement in Vietnam. If the Soviets had picked their time and nuked London and say Manchester, and launched a blitzkreig through West Germany whilst the US was distracted with a proxy war against China, would the US really have been prepared to take on the Soviets as well? I think not.
Sometimes I get the impression that little credence is given to the part the UK armed forces played in the Cold War, particularly the air force. I very much doubt that the Soviets ever had any real intention of taking on the US - very little to gain, but the UK was a big fly in their ointment for total European wide domination.