We all know that Israel suffered the tragedies of the Yom Kippur War because our leaders were locked into the “conceptzia” – the concept – that Egypt and Syria would not attack the country because they knew they would lose. Our leaders ignored reports of military formations and preparations and an urgent warning from an informed neighbor.

Today, our leaders are again burdened with a concept that distorts their policy determinations, which they cannot overcome despite the empirical evidence shattering it.

This time the concept rests in the field of demography, namely that the Arab total fertility rate (TFR) is much higher than and even a multiple of the Jewish TFR.

The Institute for Zionist Strategies (IZS) has just published the latest in a series of studies by Yakov Faitelson on demographic developments. This study, available in full at www.izs.org.il and based on the empirical data of the Central Bureau of Statistics, shows that Jewish TFR is steadily rising, while the Arab TFR is plummeting.

As noted in previous studies, this development conforms to classic demographic patterns. When a developing population benefits from modern medicine, infant mortality rates decline dramatically, life expectancy grows rapidly, TFR initially remains constant, and the population explodes.

THE DEMOGRAPHIC reality of the 1960s, ’70s and ’80s has been imprinted on the psyches and in the guts of our current leaders. In today’s empirical reality of a developing acculturated population, in which women receive formal education, in which urbanization rapidly increases, and in which other typical trends play out, the TFR sinks to a fraction.

This is today’s reality that Faitelson documents and that our leaders fail to absorb.

In 1965, Israeli Arab women were giving birth to 8.42 children on average. In 2010, they were giving birth to 3.5. Put differently, the TFR gap between the average Israeli Arab woman/ and her Jewish counterpart went from 4.95 to 0.6.

Studies by the American-Israel Demographic Research Group published by BESA, Azure and AEI, among others, and endorsed by a highly prominent US authority on demography, Nicholas Eberstadt, suggest that demographic developments on the West Bank trail those among Israeli Arabs by about three years. Remarkably the CIA reports that West Bank Arabs are more urbanized than Israeli Arabs, and for 2009, it reports a lower TFR for West Bank Arabs than the CBS reports for Israeli Arabs (3.12 vs. 3.5).

While Faitelson’s argument projects current trends to 2030 and even 2050, it is clear that even if the current trends flatten out, the Jewish and Arab fertility rates will soon converge and may reverse so that Jewish fertility exceeds Arab fertility. Even today, among 14 Middle East countries, Israel’s Jewish fertility rate ranks fifth.

Another part of the concept shattered by the IZS study is that the Jewish growth in fertility is to a considerable degree a function of haredi fertility rates. Wrong again. In fact, haredi fertility rates are declining steadily (15.3 percent between 2001 and 2009) as the overall Jewish TFR shoots upward.

THIS DEMOGRAPHIC concept is the most prominent justification by political leaders, such as opposition leader Tzipi Livni, for the necessity and urgency of a two-state solution. They claim that there will soon be a majority of Arabs between the Jordan and the Mediterranean, so that a two-state solution is necessary to ensure a Jewish majority and hence a Jewish, democratic state.

From the evidence we have seen, this is wholly refuted by empirical data. The American-Israel Demographic Research Group finds that there is a 66% Jewish majority excluding Gaza and a 60% majority when Gaza is included.

The Institute for Zionist Strategies takes no stand on the Palestinian dispute or proposed resolutions. Our mission is to develop a broad consensus for maintaining a Jewish Zionist state inside whatever boundaries exist at any given time, and we have earned strong supporters from both sides of the divide. We also understand that other, non-demographic arguments are posited for a two-state solution. But Faitelson’s current study highlights the absurdity of making national, even existential, decisions based on a concept contradicted by facts. In 1973, it took a catastrophe to shatter the concept of that day. This time, let’s do it differently.

The writer is the founding president of the Institute for Zionist Strategies. He practices law in Israel and the US.