https://www.cambridge.org/core/journals/church-history/article/one-nation-three-faiths-world-war-i-and-the-shaping-of-protestantcatholicjewish-america/D594CFEF51CA67CCE6EB1D9258BA41DB

https://content.time.com/time/subscriber/article/0,33009,801396,00.html

Given the immense cultural authority that protestants still wielded, it was their movement toward theological liberalism that proved most significant. In the decades before the war, as liberals gradually assumed positions of leadership in most of America’s major denominations, they honed a religious message that emphasized common action for the betterment of society in order to bring the “kingdom of God” to earth. A corollary to this social focus was an effort to minimize doctrinal differences. One consequence of protestants’ new social focus and pared-down theology was that it ultimately served to minimize differences with Catholics and Jews as well. Even before the war, Jewish and Catholic observers claimed feelings of closer sympathy with protestantism as a result of its new outlook, and leading protestants emphasized that a “unity of faith already exists” because “Jews and Christians” agreed with them on the essential “articles of faith.”