Having spent twenty years in uniform and even having associated with both field grade and flag rank officers, I find your belief in the eagerness of any of them to risk a charge of treason by disobeying a lawful order by the President of the United States, naïve at best and ludicrous at worst.

A properly encrypted authenticated order from the "National Military Command Center" is not subject to debate (or delay) by subordinates.

Those with the launch codes  are actually psychologically evaluated to make sure that they will launch if ordered to do so.  

The OPLAN 8010-12 "Strategic Deterrence and Force Employment". put in by Obama is basically a menu of options depending on targets.

 "The base plan (OPLAN 8010) is thought to be directed against six potential adversaries: Russia, China, North Korea, Iran, Syria, and WMD attacks by non-state actors."

https://fas.org/blogs/security/2013/04/oplan8010-12/

If the President orders a launch, there will be a launch.