Merriam-Webster defines pacifism as “opposition to war or violence as a means of settling disputes.” As long as disputes are possible and not everybody is a pacifist, the pacifist can only hope to live in peace if some non-pacifists stand on his side. In other words, being prepared for self-defense is essential to a situation of usual non-violence. (See my EconLog post “The Economics of Violence: A Short Introduction.”)

To quote Roman poet Lucan, due consideration being given to the difference between ancient (collective) liberty and modern (individual) liberty:

Ignorantque datos, ne quisquis serviat, enses

[And they ignore that swords are given so that nobody be a slave.]