(Snigger)

   The backpack nuke, the B-54 Special Atomic Demolition Munition (SADM) -
   entered into the US arsenal in 1964.

     The weapon was only 18 inches tall and 12 inches in diameter, yet
     was as powerful as a thousand tons of TNT. Special Forces units
     called "Green Light teams" would prep in using SADMs for tactical
     strikes behind enemy

     The use of SADMs was green lighted by the US military for use both
     within and outside NATO countries. In the case of an enemy advance,
     SADMs would be set off to destroy key infrastructure preventing the
     Soviets from acquiring it. Greenlight teams were also prepared to
     use SADMs to destroy installations in Warsaw Pact countries,
     including enemy bunkers, rail lines, and anti-aircraft grid
     locations.

     Some Green Light team instructors would insist their team had to
     stay within visual range of the detonation to ensure success.

   More... But don't tell those alt-right gunnut neonazi xtian identity
   folks. They might get ideas.

   [1]http://www.businessinsider.com/9-facts-about-the-uss-backpack-nukes-
   2014-2

   [2]https://en.wikipedia.org/wiki/Green_Light_Teams

References

   1. http://www.businessinsider.com/9-facts-about-the-uss-backpack-nukes-2014-2
   2. https://en.wikipedia.org/wiki/Green_Light_Teams