It seems to me that Snopes is possibly confusing two different actions in the execution sequence: the time the President has to decide to execute a counter attack versus the time from making that decision to actual missile launch. The latter is, in my opinion, what the heartburn is about among Pentagon strategic response officials.
Given the estimated 12 minute flight time of a Russian “decapitation” first strike submarine missile launch from the western Atlantic, the counter strike force must be in flight and clear of the missile silo launch area to avoid destruction. You can tease the process of the counter strike into discrete steps, evaluate how long each will take - primarily through testing- and assign maximum decision/execution times to each:
It takes this much time to detect the attack missile exhausts as they ascend on their way to US targets.
It takes this much time for STRATCOM to assess the incoming data and decide an attack is underway.
It takes this much time to to notify the President that an attack has been launched.
It takes this much time the communicate the counter attack order back to STRATCOM.
It takes this much time to communicate and confirm the launch orders all the way down to the individual missile silos/platforms.
It takes this long to actually launch the missiles.
It takes this long for the missiles to get far enough away so that they are not going to be affected by attacking missile warhead detonation.
The only thing you cannot test is how long the President will take to make the decision to order the counter strike. You can only define a maximum time available based on what remains of the 12 minutes after the time required by all the other steps is deducted.
What you can do is work very hard to shorten the testable legs to give the President the maximum time possible to reach the decision. This is because because execution is irreversible once the attack order is given and the solid rocket motors are ignited.
Our enemies are not stupid and probably have a decent idea of how long each step in the process is going to take. What they lack is confirmation that their estimates are accurate. This uncertainty exists because of the efforts being made to shorten the counter strike decision process. The detail of these efforts are classified as are the actual performance improvements to the systems involved.
By her remark during the debate, Hillary inadvertently confirmed how short the time is to get US missiles into the air once the counter strike decision is made. I’m assuming this information is classified unless, of course, one of her enablers removed the “C” from the document. < /sarcasm>