Complex sentence: Entering the United States Navy during World War II, after the war he served as a presiding judge in 1947 for the Einsatzgruppen Trial in US military court at Nuremberg.
Split into simpler sentences: Entering the United States Navy during World War II, he served in the military justice system. Beginning in 1947, he served as a presiding judge for the Einsatzgruppen Trial in US military court at Nuremberg.