But it stems from Israelis' growing fear of defeat by demographics, a concern underlined by Jewish Agency statistics that show Jewish immigration, a bulwark of Zionism, is in decline.
The Jewish Agency, which was created to promote the immigration to Israel of Jews all over the world, has conceded that the era of mass immigration by Jews is over. This peaked in the 1990s when hundreds of thousands of Jews -- and many non-Jews -- flooded into the country after the Soviet Union collapsed.
"The days of mass immigration are behind us for good," Jewish Agency head Natan Sharansky, the former Soviet dissident who spent nine years in prison before being released in 1986 and allowed to emigrate to Israel. He took over the agency as chairman June 25, 2009.
"We are not in the business of saving Jews from pogroms or from a holocaust or from persecution," he told the Financial Times.
These days, he said, "94 percent of Jews live in the free world. These people can make their choice of whether to live in Israel or not."
This year, the Jewish Agency expects around 18,000 Jews to move to Israel from the United States and elsewhere and the number is likely to dwindle.
Israel's demographic makeup has undergone dramatic change in recent years. Out of a population of around 7 million, one-fifth are Palestinian Arabs. Another large minority is made up of immigrants from the former Soviet Union who are non-Jews as defined by Jewish religious law, or Halaka.
In 1999, Sharansky, then interior minister in a coalition government headed by Labor's Ehud Barak, said 25 percent of the nearly 1 million immigrants from the former Soviet republics at that time weren't Jewish under religious law, although most had a spouse, father or grandfather who was.
As efforts to find a two-state solution -- a Palestinian state existing alongside a Jewish one -- have run into difficulties, in particular Israel's refusal to relinquish the war-won West Bank to become part of a Palestinian state, the idea of a one-state solution has gained traction.
But the Israelis understand that, given the two sides' current birth rates, the combined Arab population of Israel and the West Bank would outnumber the Jewish component within a few years.
Roughly speaking, a single state between the Jordan River and the Mediterranean would contain 5.5 million Jews and 4.5 million Arabs.
Israel's president, lifelong leftist Shimon Peres concluded in 2009 that "the one-state solution has enough intrinsic flaws to render it no solution at all."
In the general scheme of things, it would seem natural for the Israeli liberal Left to favor such a solution.
But Jonathan Cook, a British writer and journalist who has lived in the Arab town of Nazareth in the Galilee since 2001, observes that the debate over the once-taboo concept of a one-state solution has shown its fiercest opponents are of the Left.
"What the new one-state debate reveals is that, while some on the Right -- and even among the settlers -- are showing they are now open to the idea of sharing a state with the Palestinians, the Left continues to adamantly oppose such an outcome …
"The Right is beginning to understand that separation requires not just abandoning dreams of a Greater Israel but making Gaza the template for the West Bank.
"Excluded and besieged, the Palestinians will have to be 'pacified' through regular military assaults like the one in Gaza in winter 2008 that brought international opprobrium on Israel's head," Cook wrote.
"Some on the Right believe Israel will not survive long causing such outrages."
It was, after all, Israel's Labor founders, such as David Ben Gurion, who were behind the mass expulsion of Palestinians in 1948-49.
The controversial "security wall" the Israelis are building across the West Bank, absorbing large swathes of it, was the brainchild of Barak, currently defense minister and leader of the Labor Party.
The Right may still seek Jewish domination, but, says Cook, "it may be more willing to redefine its paradigms than the Zionist Left."
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