Short answers, pulled from the story.
Alexander McCaul wrote a letter on the 17th of October 1821 that introduced the phrase Judæo Christian. This specific document used the term to describe Jewish converts who had adopted Christianity.
The term became part of American civil religion by the 1940s and rose to greater prominence during the Cold War era. Leaders used the phrase to express opposition to communist atheism while distinguishing the United States from fascism and communism in Europe.
Abba Hillel Silver published Where Judaism Differs to clarify distinctiveness while Leo Baeck released Judaism and Christianity with similar motivations. These critics argued the term perpetuates notions of supersessionism and obscures critical distinctions between the two religions.
Jewish chaplains worked with Catholic priests and Protestant ministers during the war to address servicemen who had never seen or heard a Rabbi speak before. A 1948 postage stamp commemorated their heroism with the words interfaith in action as they recited prayers in Hebrew while standing arm in arm in prayer.
Conservative Protestant theology views Jews as God's chosen people with special biblical status where God promises to bless those who bless Abraham. Evangelicals believe this promise includes the descendants of Abraham and see Israel as the instrument through which prophecies of the end times are fulfilled.