In 1948, prime minister David Ben-Gurion declared independence in defiance of demographic fatalism, which was perpetrated by the country's leading demographers. He rejected their assumptions that Jews were doomed to be a minority between the Jordan River and the Mediterranean, that a massive aliya wave was not feasible, that the Jewish fertility rate was declining to below reproduction levels and that the Arab fertility rate would remain the highest in the world, irrespective of modernity. Instead, Ben-Gurion highlighted demographic optimism and aliya as top national priorities, coalesced a solid Jewish majority and planted the seeds that catapulted Israel to a Middle East power, highly respected for its civilian and military achievements. In 2005, in capitulation to demographic fatalism, prime minister Ariel Sharon retreated from Palestinian terrorism, uprooting 10,000 Jews from Gaza and Samaria. Sharon abandoned his lifelong ideology of defiance, subordinating long-term strategy and security concerns to doomsday demography. Thus, he facilitated Hamas's takeover of Gaza and its ripple effects: slackened posture of deterrence, intensified shelling of southern Israel, the 2006 Second Lebanon War, 2008's Operation Cast Lead, the Goldstone Report and the exacerbated global pressure on Israel. DEMOGRAPHIC ASSUMPTIONS have played an increasing role in shaping national security policy since 1992. But what if these assumptions are dramatically wrong? For example, since the beginning of annual aliya in 1882 - and in contradiction to demographic projections - the Jewish population between the Jordan River and the Mediterranean has grown 238-fold, while the Arab population increased only sixfold. Since 1948, the Jewish population has increased almost tenfold, and the Arab population has expanded threefold. Israel's demographers did not believe that a massive aliya would take place in the aftermath of the 1948/9 war. One million Jews arrived. They projected no substantial aliya from the communist bloc during the 1970s. Almost 300,000 Jews arrived. They dismissed the possibility of a massive aliya from the USSR, even if the gates were opened. One million olim relocated from the Soviet Union to the Jewish homeland during the 1990s. Contrary to demographic assumptions, a rapid and drastic decline in Muslim fertility has been documented by the UN Population Division: Iran - 1.7 births per woman; Algeria - 1.8 births; Egypt - 2.5 births; Jordan - three births; and so on. The Arab fertility rate in pre-1967 Israel declined 20 years faster than projected, and Judea and Samaria Arab fertility has dropped below 4.5 births per woman, tending toward three births. Precedents suggest that low fertility rates can rarely be reversed following a sustained period of significant reduction. At the same time, the annual number of Jewish births increased by 45 percent between 1995 (80,400) and 2008 (117,000), mostly impacted by the demographic surge within the secular sector. The total annual Arab births in pre-1967 Israel stabilized around 39,000 during the same period, reflecting the successful Arab integration into the infrastructure of education, employment, health, trade, politics and sports. AN AUDIT of the documentation of Palestinian births, deaths and migration, which is conducted by the Palestinian Authority ministries of Health and Education and Election Commission, as well as by Israel's Border Police and Central Bureau of Statistics and by the World Bank, reveals huge misrepresentations by the Palestine Central Bureau of Statistics. For instance, the PCBS's census includes about 400,000 overseas residents who have been away for more than one year, ignores high net-emigration (28,000 in 2008, 25,000 in 2007, etc.) and double-counts some 250,000 Jerusalem Arabs, who are also counted by Israel. Furthermore, a 40,000-60,000 annual birth gap is confirmed between PCBS numbers and the documentation conducted by the PA Health and Education ministries. The audit of Palestinian and Israeli documentation exposes a 66% bend in the current number of Judea and Samaria Arabs - 1.55 million and not 2.5 million, as claimed by the PA. It certifies a solid 67% Jewish majority over 98.5% of the land west of the Jordan River (without Gaza), compared with a 33% and an 8% Jewish minority in 1947 and 1900, respectively, west of the Jordan River. An 80% majority is attainable by 2035 with the proper demographic policy, highlighting aliya, returning expatriates, etc. In conclusion, demographic optimism is well-documented, while demographic fatalism is resoundingly refuted. There is a demographic problem, but it is not lethal, and the tailwind is Jewish. Therefore, anyone suggesting that there is a demographic machete at the throat of the Jewish state and that Jewish geography must be conceded to secure Jewish demography, is either grossly mistaken or outrageously misleading. The writer is executive director of Second Thought, which researches national security aspects of Judea and Samaria.