Before the attack on Pearl Harbor, Hurley was considered the most outspoken interventionist among the American Catholic bishops. He made enemies among isolationist Catholic clergy and laity by labeling the Nazi Party "public enemy No. 1" of the United States and the Catholic Church. He declared, "The foe of all we love, both as Americans and as Catholics, is the Nazi. Communism is still our enemy but ... in point of urgency if not in point of teaching, communism has now ceded its primacy to national socialism." In an editorial in his diocesan newspaper in 1943, he became the only Catholic bishop to issue a clarion call to Catholics to speak out against the extermination of the Jews taking place in the Nazi concentration camps, claiming that "the very basis of the Roman Catholic faith" compelled Catholics to challenge the "orgies of extermination" being perpetrated against the Jews.