Zvi Yehuda Kook and Yeshayahu Leibowitz shared much in common during lives that spanned most of the 20th century. Both were Orthodox Jews living in Israel, both attracted a loyal following and both embraced extremes in their ideologies and aroused controversy. Yet, in the end, Kook and Leibowitz differed sharply over their vision of what Judaism and what a Jewish state should be in the modern epoch. Kook, son of Abraham Isaac Kook - the great theologian of religious Zionism - followed in his father's footsteps, becoming a rabbi known for his devout belief that the modern State of Israel was the first flowering of God's Redemption of the Jewish people. According to the younger Kook, "Zionism is a heavenly matter" and "the State of Israel is a divine entity, our holy and exalted state." At the helm of the Mercaz Harav Yeshiva until his death in 1981, Kook was the spiritual father of Gush Emunim, the fervent movement among young religious Zionists to settle Judea and Samaria, lands captured in the 1967 Six Day War that Kook believed could never be returned to the Arabs for any reason; to return the land of the Bible would be to sabotage God's messianic plans for His nation. As fervent as Kook was in his belief that Israel was a holy state, Leibowitz was equally adamant that the opposite was true. "The state," he wrote in a 1975 essay on the modern political entity of Israel, "has no religious value." A professor who headed the Biological Chemistry Department at the Hebrew University, Leibowitz often called for the separation of religion and state in Israel, and censured Israel for the occupation, in his eyes, of Palestinian land in the West Bank and Gaza. Before his death 14 years ago this month at the age of 91, Leibowitz was the country's most controversial intellectual. The fury he aroused in his time was even more than that which Avraham Burg has stirred with his recent acid-penned Hebrew tome Defeating Hitler. Burg, influenced by Leibowitz, is highly critical of modern Israel, and wants the nation to abolish its identity as a Jewish state. STANDING AT their own extremes, Kook and Leibowitz opposed each other on the nature of the relationship between the Zionist state and Judaism. Perhaps, however, both men were addressing the issue in the wrong way. Zionism is both an outgrowth of Judaism and a decisive break with Jewish tradition. The early Zionists, most of whom were alienated from traditional Judaism, secularized and nationalized key dogmas in Judaism and the holidays of the Jewish calendar. They took concepts in Judaism such as messianic redemption and the ingathering of the exiles and, in a break with tradition, placed the Jew, rather than God, at the center of a modern political ideology. Secular Zionism owes a great debt to Judaism and the history of Jewish faith in 2,000 years in the Diaspora. Without the core theological idea of the centrality of Jerusalem in the Jewish worldview, the Zionists would have had no doctrine on which to base their ideology. If there had been no Jewish yearning for a Messiah and hope for Jewish sovereignty over the Land, Zionism could never have emerged as a mass movement among the Jews. Tel Aviv, the first modern Jewish city in Israel, owes a great debt to Jerusalem, the focus of Jewish faith for so many centuries. Judaism grounds Zionist identity not only in a 150-year-old national movement based on European models but in a tradition that dates back more than 3,000 years and has preserved the Jewish people for millennia. At the same time, Judaism has benefited in a tremendous way from the rise of the Zionist movement and the State of Israel. Although Israel is a country founded by socialists who were not religious, the modern state has energized a Judaism that might not have recovered from the disaster of the Holocaust if there had been no emergence of a Jewish state. The modern, democratic State of Israel has provided the inspiration and the framework for Jewish life to thrive all over the world. Israel has become central to Jewish identity for Jews everywhere. THE CHALLENGE today for religious Zionists is not to build a third temple but to apply halacha to a sovereign Jewish state. The Zionist dream, once shunned by Orthodox and Reform Jews, has revived Jewish tradition. There could be no Jerusalem to inspire Jewish faith without the reality of secular Tel Aviv. Zionism has strengthened Judaism. To speak in the extreme language of Rabbi Kook and Professor Leibowitz is dangerous and self-defeating. Whether the state is supremely holy or whether it has no theological meaning at all doesn't matter in the end. We must go beyond the realm of theory and explore ways in which secular Zionism and Jewish tradition need each other to survive and thrive. Zionism and Judaism are neither identical nor are they standing in total opposition to each other. While Israel is a modern democracy in which the Torah is not and should never be the law of the land, Judaism must still play a central role in Zionist identity. Perhaps the socialist founders of the state believed that Judaism would one day disappear as a medieval anomaly, but that has not happened. Rumors of the death of Jewish faith - and Zionism - are premature. The State of Israel must look for creative and constructive ways to link the worldviews of secular Zionism and Judaism. There will always be tensions between the two, but there is also the reality that Jerusalem and Tel Aviv cannot exist without each other. Jews all over the world must find a way to build bridges between ancient tradition and modern political ideology. The writer, based in Florida, is an adjunct lecturer on Jewish history at Broward Community College.