It was opposition to a war in Lebanon that made Israelis first sit up and take notice of Peace Now.
Now, nearly a quarter of a century later, some of the founders of Peace Now find themselves again consumed by Lebanon - but this time, they are running their first war.
Perhaps this should come as no contradiction. The Israeli left reinvents itself at every war. Particularly, wars fought in Lebanon.
Still, there is something qualitatively different this time.
It's not only the fact that among the first leaders of Peace Now were Defense Minister Amir Peretz, formally the architect, chief engineer and standard bearer for the war, and his close cabinet associate Education Minister Yuli Tamir, one of the government's most effective and vocal advocates for the Lebanon campaign.
It's also the fact that Peace Now itself has gone on record as declaring this war justified. Earlier this week, as shocking footage of the Qana killings was screened on news broadcasts the world over, Peace Now Secretary General Yariv Oppenheimer was asked why he wasn't out demonstrating for an end to the war.
"It is certainly difficult for me with the pictures, certainly with the pictures," he told Israel Radio, referring to the images of the corpses of children, the disabled and others who had huddled together in the building when the Israeli bombing began.
"Still, I believe that Israel is doing what it should be doing, defending its international border in the north. Until there's some possibility of an agreement that speaks of security in the north, I don't think that it's possible to end this operation."
It is clear that those on the left who voice support for the war are fighting another battle as well - a struggle for the very survival of the core philosophy which has driven Israeli doves since the Six-Day War: the principle that a return to Israel's pre-1967 borders is the genuine basis for lasting peace and security.
A year ago, the concept received its stiffest test - and its greatest repudiation - when a nationally traumatic full Gaza Strip withdrawal to internationally recognized borders was immediately followed by more than a thousand Palestinian rocket attacks aimed at Peace Now members resident on leftist Negev kibbutzim, as well as Sderot, home town of Amir Peretz, who is among the strongest advocates of the disengagement.
The rocket barrages and other Palestinian strikes would ultimately put the novice defense minister in the position of re-invading Gaza shortly after assuming office.
Peace Now's argument that withdrawal is necessary for peace and security is now under even more violent attack along a border Israel had largely forgotten about in the six years since the Israeli pullout.
Hezbollah's effective war against Peace Now's philosophy has opened a second front with much more potent weaponry, with 100kg explosive warheads landing deep in northern Israel, and people as far south as Haifa, Tiberias, and Afula sleeping in underground bomb shelters for fear of being killed just for sleeping in their own beds.
Again it is Peretz, an eloquent opponent of Israel's 1982 onslaught in Lebanon and the 18-year occupation that followed, who is issuing the orders, this time directing huge reinforced infantry brigades along three eerily familiar corridors in south Lebanon.
The war has engendered vocal doubts over tactics and goals. But Oppenheimer is undeterred in his defense of the Peace Now creed, and of the Israeli campaign.
"This war may not be the wisest thing, but it is certainly a justified war," he said.
"We on the left are always telling the public that on the day we leave Judea, Samaria and Gaza, we will have the right to defend ourselves from the international border. This is exactly what we've done in Lebanon. We are defending the international border. There is no element here of occupation or taking of land, therefore, regarding the legitimacy of the operation, the operation is legitimate.
"This is the reason why Peace Now and most of the organizations of the left are not demonstrating against the war."
Yuli Tamir, long known as one of the more dovish figures in the Labor Party and certainly in the cabinet, has no qualms when asked if she can wholeheartedly support the war.
"Yes, certainly," she said this week. "We have no other alternative if we want to distance the north of Israel from the range of Katyushas."
"We left Lebanon. We did not conquer, nor did we violate the rights of another people. Another people is violating our rights. In any sense of international justice and a universal view of rights in which I believe, we are in this case not only right, but are doing the same thing that any normal nation would do.
"We are defending our border."
As the war bleeds on, however, there are mounting indications that the left may be heading for another in a long history of painful rifts and internal battles. Prominent voices in Peace Now have begun to make known their opposition to the war, none more stridently than former Meretz MK and ex-Peace Now political secretary Mossi Raz:
"Every time someone mentions that Peretz comes from Peace Now it makes my blood boil."
Added Tzali Reshef, and ex-Labor lawmaker and a founder of Peace Now, in a manifesto on the organization's Web site this week:
"I'm not a pacifist. At certain times, in certain conditions, and without other options, in order to protect your life, your security, your future, your right to live in peace, there is no alternative but to fight. In Lebanon this situation came to be. But will the war, which as I said is justified, continue to be justified without thought to the amount of force used? Is the destruction of an entire neighborhood in Beirut justified? When lacking clear military targets, is it justified to choose targets without distinction? The answer is no."
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