First: War is unaccptable. War is never the best course of action. War is bad. All the same goes for violence.
That being said, it may be impossible to initiate and win a war...
in war, an offensive posture will almost certainly defeat a defensive posture, and here is why:
to defeat the enemy, lest assume you must kill them (permit metaphor and this isnt so difficult)
For a party in an offensive posture, there is a necessary/unavoidable series of events which will lead to victory, in an offensive course of action, identification and plans for exploitation of the enemy's weaknesses is a precursor to engagement. upon engagement, the military's immediate course of action is killing the enemy (via execution of the "plan").
Now, the party in the defensive posture has their own unavoidable steps towards victory. First and foremost, they wait. They wait to be attacked. maybe with some minor scout type excursions but no real offensive moves (for they would no longer be in a defensive posture and this discussion irrelevant). Once the enmy has initiated engagement, the defensive party must now identify the enemys weaknesses, plan the weaknesses exploitation, and finally execute the exploitation. all the while, the offense is killing off the defense. this series of events can take an hour, or even just a few seconds. So all this in place, for every 1 action the offense makes, the defense must make 3. Which, all things being equal, means a 3 to 1 kill ratio. In reality there are endless strategic adjustments that can be made to even and to reverse this ratio. regardless this is the starting point for war. Advantage - Offense. Furthermore, the offense has another luxury. At any point, the offense can choose to disengage and reset their assessement and plan, then redeploy their execution. the defense does nothave this option. if things are not going well, the offense pauses the engagement and resets their advantages. if things are not going well for the defense, they get killed.
This is where the catch is. Once achieving victory, the offense necessarily assumes a defensive posture. victory does not end a war. victory ends a battle. for a war to end, BOTH parties must cease fighting. if thedefeated party, no matter how small, continues to be "at war" then they will be assuimng the offenisve posture versus the victors, who are now in a defensive posture. theis goes along with the 3 to 1 kill ratio advantage. so i conclude that "all things being equal", in order to win a battle/war from a defensive posture, one must have a MINIMUM of three times as many soldiers as the enemy. Good Luck.