Men, Karl Marx noted, make history -- but rarely as they please. Surely one of the most binding constraints on political leaders is where their countries are located, and who lives in them. Geography and demography may not make for ironclad destiny, but they are powerful and often immutable forces in shaping the fate of nations.

Before U.S. President Barack Obama embarks on his trip to Israel next week, he ought to take a quick tour around Israel's demographic neighborhood. It may just hold the key to understanding why some of Israel's leaders -- though Prime Minister Benjamin Netanyahu may not be among them -- are willing to sign on to the creation of a Palestinian state, and what sort of deal would appeal to them.

In the quest to understand Israeli demographics, there is no better guide than Sergio Dellapergola. The Italian-born researcher holds a Ph.D. in demography from the Hebrew University of Jerusalem, where he is now a professor emeritus of Israel-Diaspora relations. He has also lent his skills to the Israeli government, serving as a consultant to Israeli presidents and the Jerusalem municipality, among others.

In the run-up to Obama's trip to Israel, I asked Dellapergola to identify the 10 most salient facts about Israel's current demographic reality, and what they mean for Israel's future as a Jewish state.

1.      More than 12 million people currently live in the territory between the Mediterranean shores and the Jordan River, what is known today as Israel and the Palestinian territories. Of these, about 8 million are legal residents of Israel -- a total that includes those who live within its internationally recognized boundaries, East Jerusalem, the Golan Heights, and the Jewish population in the West Bank. About 1.6 million Palestinians live in the Gaza Strip, and about 2.3 million live in the West Bank, not including East Jerusalem. Another 300,000 documented or undocumented foreign workers and refugees also live here, mostly from African countries.

2.      Of Israel's legal population of about 8 million, 6 million are Jews, over 300,000 are non-Jewish relatives of Jews who immigrated in the framework of Israel's Law of Return, and 1.7 million are Arabs -- mostly Muslims, with Christian and Druze minorities. Of the Muslim population, about 300,000 live in East Jerusalem. Of Israel's population of 6 million Jews, about 350,000 live in the West Bank.

3.      Jews constitute 49.8 percent of the total population that lives between the Mediterranean Sea and the Jordan River -- 52 percent, if one includes non-Jewish relatives. If one excludes foreign workers and the Gaza population, Jews represent 62 percent of the total; excluding Palestinians in the West Bank, their share rises to about 79 percent; excluding the Arab neighborhoods of East Jerusalem, the Jewish share of total population would be 83 percent.

4.      The rate of population growth in the state of Israel is higher than the world's average, estimated at 1.2 percent per year. Among Jews in Israel, it is 1.8 percent -- a figure that includes both immigration and birth rates. Among Arabs in Israel, it is 2.2 percent. In the West Bank and Gaza, the annual population growth is 2.7 percent, including a slightly negative migration balance.

5.      Israel has the highest fertility rate of any developed country in the world -- each woman bears over 3 children on average. Over the last 15 years, Jewish fertility has been slowly increasing -- not just among observant Jews, but also in the highly secular city of Tel Aviv. Fertility among Jewish residents in the West Bank is above 5 children. Among Israel's Muslims, fertility has been stable or slowly declining, and currently stands at 3.5 children.

6.      Immigration to Israel continues, though not at the same pace of the major immigration waves of the past. According to Israel's Central Bureau of Statistics, 16,557 people immigrated to Israel in 2012 -- down from 60,201 in 2000. The fact is, most Jews today live in more developed countries where the propensity for emigration is low.

7.      The absolute number of emigrants from Israel has been quite steady over the last 65 years, even as the population has increased tenfold. The annual frequency of emigration from Israel -- roughly 2 emigrants per 1000 residents -- is lower than average emigration from OECD countries.

8.      Both Jews and Muslims in the Holy Land are growing more religious. According to Dellapergola's surveys, 21 percent of Jews said they are now more religious than they were earlier in life, while 14 percent said they are less religious. Among Muslims, 41 percent said they are more religious, while only 4 percent said they are less religious.

Israelis are also largely satisfied with life and optimistic about the future -- and there is no discernible divide between its Jewish and Arab populations on this point. Eighty-eight percent of Israelis declare they are satisfied -- 89 percent of Jews and 87 percent of Arabs. Among both Jews and Arabs, the more religious are happier than the less religious.

9.      The proportion of Israeli haredim, the most religious and self-segregated component of society, is growing. Today, the haredim constitute slightly above 10 percent of the total Jewish population -- however, they also constitute over 20 percent of Jews under 20 years old. In 2030, the proportion of haredim might surpass 20 percent of Israel's total Jewish population, and over one-third of those under 20.

10.  The share of Jews among the total population in Israel and Palestine is slowly decreasing. This dynamic is largely being driven by population growth in the West Bank and Gaza: Within Israel proper, the current 79 percent share of Jews is expected to diminish by just a few percentage points by 2030. But if one also includes the West Bank and Gaza, the current roughly 50-50 division will change to a 56 percent Palestinian majority in 2030. Withdrawing from the Palestinian territories, then, has a dramatic effect on this demographic balance. Israel's 2005 withdrawal from Gaza, for instance, postponed the emergence of a Palestinian majority in Israel-ruled territory by 30 years.

What Does It All Mean?

For Dellapergola, Israel's demographic future constitutes its central dilemma -- and this predicament has only been sharpened by the results of the recent election. Essentially, Israel faces two choices: It can be a conglomerate of tribes struggling against each other, or an open society that respects cultural and religious differences, where each citizen participates in building the economy and shaping the state's institutions.

Even more fundamentally, demographic trends mean that Israel can't have it all. It can't be a Jewish state, a democratic state, and a state in control of its whole historical land. It can only have two of its objectives at a time. Think of it this way: Israel can be Jewish and territorial -- but not democratic. Or it can be democratic and territorial -- but not Jewish. Or finally, it can be Jewish and democratic -- but not territorial. This third choice is the one that can conceivably lead to a two-state solution.

The demographic imperative probably appeals to Obama, a rational thinker who understands the importance of acting in the present to avoid future catastrophes. He has at least once referred to the demographic realities in his speeches on the Israeli-Palestinian conflict. But the president also knows from his own political choices that getting politicians to take risks now to prevent disasters and gain rewards later isn't so easy. 

If you've ever read Charles Dickens's A Christmas Carol, Dellapergola's projections have a ring of the Ghost of Christmas Future to them. Choices will have to be made. If they are not, Dellapergola seems to be saying that demographic realities will make the decisions, not Israel's leaders.