Sun Tzu believed that the army was the instrument which gave the coup de grace to an enemy that was made vulnerable prior the hostilities. Secret agents separated the enemy’s allies from him and conducted a variety of clandestine subversive activities that set him up for the operation.
Note especially the chapter on “Employment of Secret Agents”
>>>“Employment of Secret Agents”
“Disarm your enemy in peace by diplomacy and trade if you would conquer him more readily on the field of battle”
- Klaus von Clausewitz, father of German militarism