After all the dire demographic predictions about the shifting balance of Arabs and Jews in Israel proper and in historical Palestine west of the Jordan, there is, from the Jewish point of view, some good news. In fact, there are two good news items, one major and one minor.

The major item is a study, released earlier this month in Washington by the American Enterprise Institute and the Heritage Foundation, according to which hitherto accepted population statistics for West Bank and Gaza Palestinians have been vastly inflated. The minor item is a report, published in yesterday’s edition of the Israeli daily newspaper Ha’aretz, stating that, while the number of Jewish births in Israel remained steady in the year 2004, the number of Arab births declined relative to the previous year for the first time since 1948.

The AEI-Heritage Foundation study has already been seized upon by Israeli territorial maximalists and their supporters as proof that the much-ballyhooed demographic threat to a Jewish majority west of the Jordan is imaginary and that next summer’s planned disengagement from the Gaza Strip, let alone future Israeli withdrawals from the West Bank, are demographically unnecessary. The Ha’aretz report will be used to back this claim.

And yet while both of these items are encouraging for Israel, it would be a grave mistake to draw the wrong conclusions from them.

The central argument of the AEI-Heritage Foundation study is that all recent demographic projections for Palestinian numbers in the West Bank and Gaza Strip have been guilty of an exaggerated assessment of Palestinian population growth that has in turn been applied to a statistical base, released in 1997 by the Palestinian Central Bureau of Statistics, which was highly inaccurate, too.

The politically biased PCBS, according to this study, overstated Palestinian births, understated deaths, overlooked emigration, and counted some groups (such as East Jerusalemites) twice, once as West Bankers and once as Israeli Arabs, thus “creating” over a million fictitious Palestinians.

On top of this, it is claimed, demographers have failed to take into account a dramatic drop in recent years in the Palestinian birth rate, with the cumulative result that the 2.4 million West Bank and Gaza Arabs who actually exist have been turned into a fictitious 3.8 million Arabs. This means that the percentage of Jews in the mixed population currently living between the Mediterranean and the Jordan River, assumed to have been 64% in 1967, has fallen not to 50%, as the demographic doom-and-gloomers maintain, but to 59.5% – a level at which it now appears to have roughly stabilized.

Let us assume for the sake of the argument that all this is correct, an assumption that is in fact premature, since the new study is open to methodological challenges whose scientific evaluation may take a long time. Let us assume too, as is borne out by the Ha’aretz story, that Arab birthrates have been dropping dramatically, not only in the Palestinian territories, but in pre-1967 Israel. Does this mean that the demographic threat to Israel’s Jewish character no longer exists and can be safely ignored?

It might be helpful to think of one or two hypothetical comparisons. Suppose reliable statistics were to show that that the number of Chechens in Russia (actually, less than 1%) had leveled off at “only” 40% of the total population: Would any Russian in his right mind still make the case for retaining Chechnya as part of Russia rather than getting out of it as quickly as possible? Or suppose that two out of every five people in China (as opposed to two in every thousand) were Tibetans: How long would it take before China granted Tibet independence?

Of course, Israel is not Russia or China, and the West Bank and Gaza Strip are not Chechnya or Tibet: Historically, geographically, and militarily, the comparison holds little water. But this is beside the point. When two highly antagonistic peoples or ethnic groups inhabit the same country, there must obviously be some population ratio between them that, once exceeded by the minority, results in horrendous tensions, permanent instability, almost inevitable violence, and probable chaos and civil war.

Although it is impossible to assign a precise numerical value to the tipping point past which an aggrieved minority no longer accepts its minority status, historical experience shows us that it is well under 40%. It would be foolhardy to think that, with their history of enmity and cultural and religious difference, Israeli Jews and Palestinian Arabs would ever interact differently even if the latter were granted full democratic rights. We are not talking, after all, about two populations, like Walloons and Flemings in Belgium, or even like Bosnians and Serbians, which have more in common than the things that separate them.

What is hopeful about both the AEI-Heritage Foundation Study and the Ha’aretz report is the prospect that falling Palestinian birthrates may make it possible for an Israel that has withdrawn from the Gaza Strip and most of the West Bank to stabilize its Arab minority at somewhere near the level it is now – that is, in the vicinity of 20%. Historical experience tells us that this is still a ratio at which a minority, if treated fairly, will agree to think of itself as such and to seek integration within the majority culture.

Yet the demographic threat to an Israel that does not budge from where it is now is no bogeyman, and to oppose Prime Minister Sharon’s Gaza disengagement plan is still demographic madness. Any other way of reading the new figures is distorting and irresponsible.

Mr. Halkin is a contributing editor of The New York Sun.