Moments after Hanan Porat and his fellow Israeli paratroopers had crossed the Suez Canal as spearheads of a furious Israeli counterattack in the 1973 Yom Kippur War, he was severely wounded in an Egyptian mortar bombardment. The Egyptians and Syrians had surprised Israel on Yom Kippur, with an atrocious loss of life, and crushed the country’s post-Six Day War belief in its own invincibility.

As Porat lay recovering in his hospital bed, his chest ravaged by shrapnel wounds, he thanked God that he wasn’t in the burn unit. And then, as Yossi Klein Halevi writes in his new book, “Like Dreamers,” the next phase of Porat’s life mission was revealed.

He read, in his hospital bed, an article in a kibbutz newspaper by a writer named Arnon Lapid, titled, “An Invitation to Weeping.” Porat wasn't a member of the secular kibbutz elite; he was a member of a more marginalized group of religious Zionists, who envied the kibbutznikim, and respected them as well.

He was stunned by what Lapid wrote: “I want to send you all an invitation to weeping … I will weep over my dead, you will weep over yours … we’ll weep … for the illusions that were shattered, for the assumptions that were proven to be baseless, the truths that were exposed as lies … And we will pity ourselves, for we are worthy of pity.”

Halevi writes that when Porat read this lament he “felt as if his wounds were being torn open. He would have shouted if he had the voice. Pity the generation privileged to restore Jewish sovereignty to the land of Israel? What small-mindedness, what weakness of character! Where would the Jews be now if, in 1945, they had thought like this Arnon Lapid? Israelis would do now what Jews always did: Grieve for their dead and go on, with faith and hope.”

Porat would soon help usher into existence a new movement, a settlement enterprise that would be self-consciously modeled on Israel’s original settler movement, the socialist, Zionist and fiercely anti-religious pioneering formations that built the original kibbutzim. The early kibbutznikim were the men and women who laid the foundations for the reborn Jewish state and led that state through the first decades of its existence, but by 1973 they appeared to be a spent force, exhausted spiritually, morally and politically.

Porat’s movement, which would cover the biblical heartland of the Jewish people with settlements -- a heartland the secular world referred to as the West Bank, but which Jews knew by the ancient names of Judea and Samaria -- would be driven by devotion to God and his demands, not by a secular vision of Jews liberated from the ghettoes and freed from the fetters of capitalism.

This movement, which coalesced around Porat’s Gush Emunim -- the “Bloc of the Faithful” -- has defined Israel’s political agenda for the past 40 years, just as the kibbutz movement and its leaders shaped Israel and its priorities through the early period of its existence. What is so fascinating about these two movements is that, for all their transformative success, they have both failed to complete their missions.

The kibbutzim didn't turn Israel into a socialist paradise, and the hubris and shortsightedness of the Labor elite, which sprung from the kibbutz movement, brought Israel low in October 1973.

And the religious-nationalist settlement movement has succeeded in moving hundreds of thousands of Israelis into the biblical heartland, but it has never been able to convince the majority of Israelis that the absorption of the West Bank into a “Greater Israel” represents their country’s salvation, rather than a threat to its existence.

The thwarted utopianism of these two movements is the subject of “Like Dreamers,” which is a magnificent book, one of the two or three finest books about Israel I have ever read. Halevi tells the story of seven men -- paratroopers who participated in the liberation of Jerusalem in 1967 -- who became leaders and archetypes of Israeli’s competing utopian movements.

When I met Halevi in New York recently, I was filled with questions about what this history augured for Israel's future. The first one to cross my mind: How did the Orthodox settlers so easily supplant the leftist kibbutz elite as the nation’s pioneering vanguard?

“The left lost its vigor at precisely the moment that religious Zionism discovered its own vigor,” Halevi told me. “The key here is 1973. After 1967, not much happened. There were a couple of settlements, but the Labor government kept everyone on a tight leash, and the religious Zionists were intensely frustrated. The empowering moment for religious Zionists was due to Labor’s failures in the Yom Kippur War. A generation of young kibbutznikim came out of 1973 deeply demoralized. People like Porat realized that the left had lost the plot.”

Halevi went on, “In Israel, you never naturally evolve from one state of thinking to another. We careen. So we careened toward religious Zionism and the settlement movement.”

But in your book, I said, you suggest that the settlers have failed to gain legitimacy for their movement among the mass of Israelis. How did they fail? “The settlement movement failed during the first Palestinian uprising. Israelis realized then the price of the occupation, that there was no such thing, as settler leaders promised, as a benign occupation. That kind of illusion went in the late 1980s.”

Halevi noted one small irony here: If the first Palestinian uprising dispelled the idea that Israel could occupy the Palestinians cost-free and in perpetuity, the second Palestinian uprising -- which began after the peace process failed in 2000, dispelled the left-wing argument that territorial compromise with the Palestinians would be easily achieved once Israel opened itself to the possibility of peace.

“The second uprising was the end of the dream of the Peace Now movement, because the worst terrorism in Israel’s history happened after we made the offer for real territorial compromise at Camp David, and after the Clinton proposals, and after we offered to redivide Jerusalem, becoming the first country in history to voluntarily offer shared sovereignty in its capital city.”

So, reality has discredited both the right and left. What comes next? The next great ideological movement in Israeli history is centrism, Halevi said. “The Israeli centrist believes two things: A. the Arab world refuses to recognize our legitimacy and our existence; and B. we can’t continue occupying them. I believe passionately that the left is correct about the occupation, and I believe the right is correct in its understanding of the intentions of the Middle East toward the Jewish state.”

I argued that “centrism” possesses neither the magnetic power of socialist transformation nor the messianic qualities implicit in the settlement enterprise. Halevi disagreed. “Centrism is taking a people that hasn’t functioned as a people, hasn’t functioned as a nation, for 2,000 years -- that is in some ways an anti-people, who have so many different ideologies and ways of being -- and learning how to function as a working nation. That’s a large cause.”

Will centrist Israel overcome the power of the right? And what is its program? In a coming post, I’ll look at the ideological and practical challenges to the solutions centrism puts forward to the Israeli-Arab crisis. In the meantime, go out and read Halevi’s book; nothing explains more eloquently why Israel, more than most any other country, lives or dies based on the power and justice of its animating ideas.