On Tisha Be'av, a traditional day of mourning and fasting in the Jewish calendar, Jews around the world remember the Babylonian destruction of the First Temple in 586 BCE, the Roman razing of Jerusalem in 70 CE, and the fall of Betar - the last stronghold of the Bar Kochba Revolt - in 135 CE. Other disasters also occurred on the Ninth of Av in Jewish history. On the eve of Tisha Be'av, Jews read from the Book of Lamentations, a work of mourning for a fallen Jerusalem ascribed to Jeremiah. The ancient prophet laments, "How doth the city sit solitary, that was full of people!" Does Jeremiah's lament have any meaning to Jews today? Is the Ninth of Av relevant in a world where Jews are sovereign in the Land of Israel, Jerusalem teems with people and is far from solitary, and Jews are able to pray in the Old City of Jerusalem at the Western Wall? Why is there a need to mourn when, in fact, Jews today should be celebrating the fact that after 2,000 years a Jewish state has again arisen in the Jewish homeland? Do we really need to fast for our sins and the resulting loss of sovereignty - when, today, there is a Jewish state and a Jewish army and a Jewish parliament in the Land of Israel? I MUST admit that I have no easy answer to these questions. But I do know that Jews today still have important reasons to commemorate the destructions of the Ninth of Av. First, we must remember that in ancient times the Assyrians, Babylonians, Hellenists and Romans persecuted our people, and defiled and destroyed the political and religious center of Jewish life embodied in the Temple. The Jewish people endured much suffering as a result of these tragedies. Memory is a central component of Jewish faith. We must never forget our past, both the triumphs and the tragedies. If we do, we are doomed to repeat the past's mistakes. Memory is a central component of Jewish life and theology. The past is always present. Second, the Jews may have sovereignty over the Land of Israel, but we have not yet rebuilt the Temple. Only in an ideal age will a messiah from the line of King David lead the effort to reestablish the Temple and bring recognition of God as One to the world. Yes, Israel belongs to the Jewish people. But we are far from the ideal world of a messiah. Israel today faces a crisis of lack of leadership and a great gap between rich and poor. The State of Israel is the religious, political and cultural center of the Jewish world. But it is far from being the first flowering of messianic redemption. Meanwhile, Jews all over the world are ignorant of their history, heritage, faith and culture. This crisis of ignorance leads to assimilation and the erosion of Jewish life all over. IN THE WIDER world, people are suffering from hunger and from theological and ideological fanaticism. The reality of death permeates the news in our papers and on TV. So we must mourn a defective world and hope for better times. The Ninth of Av reminds us that we have not yet reached the ultimate goal of a world of peace and brotherhood. We have a long way to go. Third, and perhaps most important, only two generations ago Six Million Jews died at the hands of the Nazis and their collaborators. The Shoah is the worst disaster to befall the Jewish people in modern history. Today Jews have sovereignty over Israel. But the cost has been an enormous one. How can we convert the Ninth of Av into a day of celebration when the survivors of Auschwitz-Birkenau, Bergen-Belsen and Dachau still live to tell their tales of survival? As I fast on Tisha Be'av, I will try to experience in a very small way, the starvation of Jews in the ghettos of Warsaw and Lodz during the Second World War. Israelis and their friends abroad celebrated Jewish triumph on Israel Independence Day. Now comes the time to mourn for the Jews' great loss. To connect the Ninth of Av to the disaster of the Holocaust in no way detracts from the mourning for the Temples destroyed by our ancient oppressors. This connection to events of 65 years ago gives an immediacy to an ancient observance, reminding us that while the Assyrians, Romans, Hellenists and Babylonians are gone and we are still here, there are enemies today who want to destroy the Jewish people and the Jewish state. This reality gives us persuasive reason to continue to mourn on the Ninth of Av. The writer lectures on Jewish history and thought for Nova Southeastern University's Lifelong Learning Institute in Fort Lauderdale, Florida.