Complex sentence: James Schwarzenbach (1911-1994) was a right-wing, Republican Swiss politician, in the 1970s head of the short-lived Republican Movement and publicist of fascist, völkisch and antisemitic literature, his "Thomas-Verlag".
Split into simpler sentences: James Schwarzenbach (1911-1994) was a right-wing, Republican Swiss politician and publicist. He also was publisher of fascist, völkisch and antisemitic literature as the owner of "Thomas-Verlag".