With U.S. President Barack Obama seemingly determined to push for a two-state solution to the Israeli-Palestinian conflict, and Israeli Prime Minister Benjamin Netanyahu equally adamant that he lacks a real partner for peace, the United States and Israel seem destined for a clash. But there are larger forces at work than the policies of either government. The face of Israel is changing, and in ways that explain much of what is happening in the Jewish state today.

Take Avigdor Lieberman, whose rising political star befuddles much of the Israeli establishment. Despite being perennially poised on the verge of multiple indictments for financial crimes, tagged as an Arab-loathing ultra nationalist by the Israeli media, and attacked from both sides of the political spectrum as the Jewish state's very own public diplomacy nightmare, the new foreign minister's voter appeal has climbed steadily. And the popularity of his right-wing party, Yisrael Beytenu ("Israel Our Home") has grown as well, even among young, secular Israeli-born Jews. Why?

Many have offered explanations for Lieberman and Yisrael Beytenu's rise, from rocket attacks to a religious revival, but one key factor has been overlooked thus far: They have demographics firmly on their side. The party's platform taps into the fears of the country's demographically ebbing secular middle ground and feeds off of working Israelis' frustrations with the country's two most dissonant minorities -- Israeli Arabs and ultra-Orthodox Jews (haredim) -- both of which are on the demographic upswing.

Fig. 1. Projected trend in primary school student composition.

Fig. 2. Projected trend in voting-age population.

The numbers are impressive. In 1960, the Israeli Central Statistical Bureau (ICSB) reported that just 15 percent of students in the Israeli primary-school system were either Israeli Arabs or haredim. Now, about 46 percent are. Around 2020, the majority of primary-school students will likely be composed of children from those two groups, each segregated into its own segment of the school system (Fig. 1). And though, at current rates, it will be well beyond the time horizon of our current projections before these two politically disparate groups "dominate" the Israeli electorate (Fig. 2), by 2030 they are likely to be very close to composing half of all 18- and 19-year olds, the youngest tier of the electorate and the age at which Israelis are first eligible for conscription (Fig. 3a & b) -- a dramatic shift in Israeli ethnic and religious composition.

Such a development is completely contrary to the demographic hopes of Israel's secular Zionist founders, which hinged on a healthy pace of secular-Jewish childbearing and steady streams of Jewish immigrants. For the long run, the founders trusted in the powers of prosperity and modernity to turn Israel's kaleidoscopic assortment of Jewish and non-Jewish ethnic communities into a modern multi ethnic population with European-like aspirations for women and European-like levels of fertility (a measure demographers use to estimate the trend in lifetime childbirths per woman).

The demographic outcomes of six decades of nation-building and social investment are mixed. Descendents of European and American Jewish émigrés have, indeed, stayed somewhat above the two-child replacement level, unlike those who remained overseas. But Jewish immigration to Israel has been more episodic than continuous. The post-independence wave (1948-51), which brought about 700,000 immigrants to Israel's shores, was followed by nearly four decades of much lower levels and then another great wave -- from 1990 to 2000 -- of more than 900,000 émigrés, mostly from the former Soviet Union. But today, most sources put Israel's net influx at less than 20,000 immigrants per year, which accounts for about 18 percent of the country's annual population growth.

Meanwhile, the hope that fertility levels between Israel's different populations would even out has already largely been fulfilled. Although women arriving from traditional North African, Middle Eastern, and Asian Jewish communities averaged well over five children in the 1950s, their granddaughters now average fewer than three. Israeli Arab fertility, too, has dropped, albeit at a slower pace, from more than seven children per woman in the 1950s to about 3.6 today. Among Israeli Arabs, who now make up 20 percent of Israel's 7.1 million resident citizens, Muslims (83 percent of Israeli Arabs) are estimated by the ICSB at 3.9 children per woman. Arab Christians currently make up just over 8 percent of Israeli Arabs, with fertility at about 2.1 children per woman.

But there's one major outlier: the haredim population. While official statistics are unavailable, academics report that ultra-Orthodox women bear, on average, about 7 children per woman -- in other words, there has been no decline in their fertility since Israel's establishment. That the Haredim -- 7 to 11 percent of Israel's population, and growing at an estimated 4 percent annually -- are expanding faster than either Israeli Arabs or the rest of Israel's Jewish population should be no surprise. Haredi sects grew out of 19th-century movements aimed expressly at revitalizing and propagating theologically conservative Judaism and deterring secularization and conversion.