As the reasoning went, the American nuclear deterrent must
  be credible, or else the Soviets would seize the 
  opportunity and launch an unprovoked attack on the US, 
  Germany, or both. If a communication breakdown between the 
  White House and the military could render the nuclear 
  arsenal unusable, that would tend to diminish the 
  credibility of the deterrent.

If you wanted the pre-delegation of Presidential authority to increase the credibility of the deterrent though, the Soviets had to know about it. Which makes you wonder - did they strongly deny it to the public whilst quietly informing the Soviet Union about the true situation?