On 1 July 1944 Kubowitzki wrote to John W. Pehle opposing proposals to conduct aerial bombardment of the extermination camps on the grounds that "the first victims would be the Jews". Kubowitzki instead proposed that Soviet paratroopers and members of the Polish resistance be instructed to attack the installations.[2]
He served as the Secretary-General of the WJC from 1945 to 1948.[1]