During World War II, he was a conscientious objector, and served in a Civilian Public Service camp established by the Catholic Worker Movement.
Through Richard Carbray and archbishop Thomas Roberts, Zahn was introduced to abbot Cuthbert Butler, OSB.
Zahn gave talks on Franz Jägerstätter and wrote a speech for Butler, which he delivered to the Council.
Gallagher implies this all led to Schema 13 supporting conscientious objectors and denouncing weapons of mass destruction.
He later wrote In Solitary Witness: The Life and Death of Franz Jägerstätter, about the Austrian farmer and conscientious objector who refused to swear an oath to Hitler and to fight in his army.