### Clue: President's instinct at the end — no moral code (7)
### Answer: BUSHIDO 
 ### Explanation: Definition: moral code
 BUSH(George, former Presidents of the US) + ID(in psychology, that part of the mind from where instinctive impulses surface) ***plus***(at the end) O(letter representing 0/none/no).
Defn: … of the Japanese samurai.
… part of the code.