Could it be because our foreign policy is driven by the wealthiest of wealthy Jews in this country who own and/or sit on the boards of the largest global corporations in America and throughout the world. Or could it be because God intervenes in the affairs of men to bring about His perfect will, including the use of America as the lone defender/protector of the state of Israel? (Not meaning to sound ignorant or sarcastic here, but just conveying some thoughts I've been wondering about.)
If you believe in historic Christianity, as opposed to dispensationalism, then you cannot believe that our support of Israel is part of God's perfect will, because Israel was part of the Old Covenent, which was fulfilled and superceded by the New Covenent. The New Israel is the Mystical Body of Christ. Christians, and Jews who convert to Christianity, are now the heirs to Abraham and God's promise to them is salvation, not some plot of land. See Romans 11, and also the Letter to the Hebrews