For the last two decades, the easiest way to invoke dovishness in Israel has been to utter the words "Yossi Beilin." The politician who navigated mutual recognition between Israel and the Palestine Liberation Organization in the early 1990s and has never stopped believing, Beilin has a unique place in the Israeli political galaxy, both admired and reviled for his relentlessness.

So it is of some consequence that last week, as new elections were announced and the chances of a year-end Palestinian-Israeli agreement seemed slim to nonexistent, Beilin revealed that he was leaving Parliament 20 years after he was first elected and stepping away from political life 31 years after Shimon Peres named him the Labor Party's spokesman.

Israel's political landscape has changed drastically since the 1970s. Peres, now the country's ceremonial president, and Beilin, a member of the declining leftist Meretz Party, have both abandoned Labor, whose own fortunes have been sinking steadily.

Still, Beilin's decision to leave public life and set up a private company offers a lens through which to view Israeli politics. The arc of his career reflects the fortunes of peacemaking. He said last week that he was leaving in triumph, since his support for an end to occupation of Palestinian territories and the creation of a Palestinian state, once radical positions, are today mainstream. There is no denying that shift in public opinion and official policy. But it is impossible not to see the move also as a defeat - of Beilin's understated style in an overheated environment, and of his goals, with no Palestinian state on the horizon.

Most successful Israeli politicians resemble Ariel Sharon - open-shirted men with strong military backgrounds, thick fingers and quick tempers. But the soft-voiced Beilin, with his elegant gold pens and carefully knotted ties, was a different species, one that left Israelis bemused. At his political height, that mattered little since he was less a leader of the people than a leader of the leaders, a behind-the-scenes actor who persuaded Prime Minister Yitzhak Rabin in 1993 that Yasser Arafat wanted peace. That feat was all the more remarkable because, as Beilin noted in a two-hour conversation in his office last week, he and Rabin never liked each other.

It is a tribute to Beilin - to his powerful intellect and keen interpersonal skills - that despite his demure style and lack of good-old-boy credentials, his political fortunes rose remarkably in the 1990s as the Oslo peace process that he set in motion took over Israeli politics. In the Labor primaries at one point, he won the No.2 spot. Twice he was appointed a minister. For a while, if you wanted to know what was next on Israel's geopolitical agenda, you consulted Beilin.

But when peacemaking reached a dead end and the second intifada broke out in late 2000, sending Israel into a fury of suicide bombings and fierce military counterattacks that killed thousands, Beilin lost his sheen. He was accused of being a snake-oil salesman, responsible for luring Israelis into the false belief that they had a peace partner. The exotic fellow with the Ph.D. and attaché case was anathema.

Beilin said he felt betrayed by the Palestinians but that Israel had mishandled things as well. He argued that nothing essential about the situation had changed, that a deal remained possible. He found a new home in Meretz and continued his work. But he never recovered his place in public life, even after negotiations with the Palestinians again took center stage. Three years ago, the new Kadima Party of Sharon and Ehud Olmert came to power, and its outlook today seems hard to distinguish from his.

When Olmert gave a departing newspaper interview in September, he sounded exactly like the Beilin of the last 20 years.

"I could not have said it better than he did," Beilin mused last week. "I told him that sometimes I read his speeches and am not sure that I didn't write them."

But even Beilin recognizes that while his successors may sound like him, they are not taking his advice on details and tactics. He recoils, for example, at arguments against yielding any part of East Jerusalem to the Palestinians.

"Israel is going to pay a crazy price because it is not ready to give up some Palestinian neighborhoods in Jerusalem that no Jew has ever visited," he said. "Yet giving up on that means giving up 250,000 Palestinians who don't want to live under Israeli sovereignty."

He sees two clocks ticking. One is demographic, with the Jewish-Palestinian ratio in Israel and the Palestinian areas nearing 50-50. The other is geopolitical, what he calls the growing threats and hatred toward Israel in the region.

"Our behavior," he said, "is costing us a huge price because we are giving the fanatics the best pretext."

Beilin, now 60, is starting a consulting firm and says he plans to stay involved as a private citizen in peace efforts, even as he promotes businesses across the Israeli-Arab divide.

Among those who favor peace, it is widely feared that the most Israel will ever offer the Palestinians is less than the Palestinians will ever accept. Still, Beilin argues that there is simply no other choice than a deal.

He notes, with approval, that security cooperation in the West Bank between Israel and the Palestinians is growing, with Jordanian and American help. He argues for a peace accord as soon as possible, followed by a cease-fire with Hamas in Gaza, despite what he considers its vicious ideology.

He says he fervently hopes for a victory by Barack Obama - but also that the economic and other crises do not overwhelm the new administration.

"God forbid if this conflict is marginalized," he said. "If we are marginalized, it will be to kill each other."

Beilin's colleagues on the left, meanwhile, publicly mourn his departure and worry about its symbolism but also recognize that it reflects reality.

"He saw the promised land," wrote Gideon Levy, a leftist columnist in Haaretz, "but he did not reach it."