The Radical American Judaism of Mordecai M. Kaplan - Hardcoverby Mel Scult (Author) Mordecai M. Kaplan, founder of the Jewish Reconstructionist movement, is the only rabbi to have been excommunicated by the Orthodox rabbinical establishment in America. Kaplan was indeed a radical, rejecting such fundamental Jewish beliefs as the concept of the chosen people and a supernatural God. Although he valued the Jewish community and was a committed Zionist, his primary concern was the spiritual fulfillment of the