There are certainly many factors that impacted America and contributed for it to tie itself between the Arab-Israeli conflict throughout history. One of the most important and culturally relevant ones is the sense of a parallel narrative between the Israeli struggle to prosper in their tiny land surrounded by the imposing Arab states; and the American spirit as a historical pioneer in the battle for freedom and democracy. America and Israel share a powerful and fundamental connection to the ideal of human freedom and the faith in a democratic way of life.
Another major factor, was the growth of Christian Zionism in America during the mid-20th century. The evangelical movement started establishing positions that leaned towards the need to protect and assist Israel, believing that this would actually bring us closer to a return of Jesus. This emphasized the importance of Israel's subsistence and prosperity to Christian prophecy. Many influential figures of those times repeatedly pushed the message that standing against Israel would mean standing against God, and God would treat nations the way they treat Israel.
Israel as "The Holy Land" matters immensely to the U.S. on a symbolic level, as America has a long history of imagining itself as the New Israel/Promised Land.
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