I attended a forum recently where an Israeli Jew was criticizing the human rights record of the Israeli government.
At the end, I asked him this question. "If you wished to live in a multi-cultural society where women have full rights, religious and ethnic minorities have full rights, everyone has access to courts, the press was free, and the judiciary was fairly honest, would you prefer to live in Syria, Egypt, Jordan, Lebanon, or Israel?" (These are Israel's immediate neighbors.)
He would not give a direct answer, and I asked twice, "Please, sir, will you answer the question?"
I had attended with an anti-Israeli lady and her blind friend. Later, during a polite but intense discussion with other Jews and Palestinian Arabs, the blind lady sidled up to me and murmured "You know, that guy never did answer your question."
America sides with Israel because Israel is the nation in that region that is most like us. Not perfect, just fairly free and fairly honest, and fairly trustworthy, a muli-ethnic democracy.