FRA, West Bank -- Not long ago, at a West Bank settlement outpost surrounded by barbed wire and guarded by dyspeptic German shepherds, I attended a joyful event: a brit milah, the circumcision of an eight-day-old boy. This outpost was home to just a handful of families, but more than 100 people came to celebrate with the boy's parents.

Many of the visitors made the rough trek through Arab villages to get to this hill. These young settlers are the avant-garde of radical Jewish nationalism, the flannel-wearing, rifle-carrying children of their parents' mainstream settlements, which they denigrate for their bourgeois affectations - red-tile roof chalets, swimming pools, pizzerias - and their misplaced fealty to the dictates of the government in Jerusalem. These new pioneers set out for the Samarian mountains and the hills of Hebron, where they live in log cabins and broken-down trailers, in settings sufficiently biblical and remote to allow for the cultivation of a new variant of apocalyptic zealotry.

The mohel's table stood at the rear of a double-wide trailer that serves as the outpost's synagogue. I stood by the door, near the tables holding plates of hummus and bottles of schnapps. I fell into conversation with an acquaintance of mine, a woman named Ayelet, who is in her late teens, pregnant, the daughter of a former assistant professor of history at City College. She is a resident of an outpost in the radical settler heartland near Nablus. We were interrupted by the newborn's father, a goat farmer, as he began giving a d'var Torah, an interpretation of a Bible passage. He turned, rather quickly, to the threat posed by the Amalekites, the eternal enemy of the Jews, a tribe that, according to the Bible, attacked Moses and the Children of Egypt on the exodus from Egypt.

"Amalek," in the language of the settler hardcore today, often stands for the Arabs, the existential enemy of the Jews. "I am looking at our life today, and what Amalek wants to do is swallow up the people of Israel," the father said. "This is the snake. This is the snake."

I turned to Ayelet. She wore a long skirt, her hair was covered, and she carried an M-16. I asked her if she thought Amalek was alive today. "Of course," she said, and pointed out the door, toward an Arab village in the distance. "The Amalekite spirit is everywhere. It's not just the Arabs."

Who else, then? "Sharon isn't Amalek," she said, "but he works for Amalek."

I had not seen Ayelet before with a rifle. She told me it belonged to her husband, Akiva, who couldn't be here, because he was in court in Jerusalem. He was, she said vaguely, answering charges related to his work for Kach, the racist movement founded by the late Meir Kahane.

I asked her if she would use the M-16 only against Arabs, or against Jews who came to tear down her outpost. "God forbid," she said. "We wouldn't want to hurt a Jewish soldier."

What about a Jewish prime minister?

"Sharon is forfeiting his right to live," she said.

I asked her if she would like to kill him.

"It's not for me to do. If the rabbis say it, then someone will do it. He is working against God."

Over the past year, I've heard at least 14 young Orthodox settlers - in outposts, and in yeshivas in the West Bank and Jerusalem - express with vehemence a desire to murder Prime Minister Ariel Sharon and his men, in particular the deputy prime minister, Ehud Olmert, and the defense minister, Shaul Mofaz. I've met several more who actively pray - and, I suspect, work - for the destruction of the Dome of the Rock, the Muslim shrine on Jerusalem's Temple Mount. And I have met dozens more who would not sit shiva, certainly not for the Dome, but not for their prime minister, either.

The threat of the radical right has become a matter of terrible urgency in the Israeli government. Avi Dichter, the chief of the Israeli internal security service, has been for months running around - to borrow a phrase from George Tenet - with his hair on fire over the threat. He has warned of the potential for attacks against the Dome of the Rock and the Al Aksa Mosque, on the Temple Mount; such a strike, he said, would set off global war between Muslim and Jew - a goal the radical yeshivas of the West Bank share with Al Qaeda.

Mr. Dichter told a Knesset committee last month that his agents believe there are 150 to 200 settlers hoping to kill Mr. Sharon. A member of the committee asked, "If we were talking about Palestinians and not Jews, would you place these people in administrative detention?" Mr. Dichter answered, "Absolutely."

Now, there is surely something strange about an Israel in which Ariel Sharon, the invader of Lebanon and the father of settlements, is in mortal danger from the right. And it should be noted that Mr. Sharon's withdrawal plan has flaws and limitations. Yet what is most interesting here is that the settlers grasp something about the plan that Mr. Sharon's critics on the left do not, which is that Mr. Sharon poses a greater threat to theologically motivated settlers than even Yitzhak Rabin.

The difference between Mr. Rabin - who was murdered on the altar of settlement nine years ago - and Mr. Sharon is the difference between bilateralism and unilateralism. Mr. Rabin's plan depended on Yasir Arafat, and he undoubtedly would have come to see Mr. Arafat as no partner for peace. But there is only one indispensable man in Mr. Sharon's plan, and that is Mr. Sharon himself. If Mr. Sharon evacuates a settlement - and if the sky does not respond by falling - the logic of dismantlement may take hold; a majority of Israelis already support the unilateral shutting of many settlements.

Which is why the Orthodox right is in panic. The rabbi of the Old City of Jerusalem, Avigdor Neventzal, announced in June that anyone who gives up a part of the land of Israel - even a single settlement - to a non-Jew could be the target of a religiously sanctioned murder. The official spokesman of the Jewish community in Hebron, David Wilder, wrote in June: "Nobody wants violence. Especially against our own brethren. But it's time to wake up. The reality is, if Sharon insists on trying to implement his 'Jewish transfer' from our homes and land, it's going to happen."

In the summer of 1995, Yitzhak Rabin was more or less alone. The man who led the Israeli Army to victory in the Six-Day War - making possible the settlement movement in the first place - was called a Nazi at public rallies; radical Orthodox rabbis cursed him; and much of world Jewry was silent. Today, once again, the atmosphere is one of tolerance for murder. "God's name is being invoked against Sharon, but where are the rabbis?" asked Abraham Foxman, national director of the Anti-Defamation League and one of the few American Jewish leaders to take heed of Mr. Dichter's warning.

The extremist yeshivas that give rise to fundamentalist thuggery are financed in part by Orthodox Jews in America. Several Orthodox rabbis in America took the lead in demonizing Mr. Rabin. And Meir Kahane, the inspiration for so much fanaticism, was an Orthodox rabbi from Brooklyn.

The mainstream Orthodox rabbinate - in America and in Israel - failed nine years ago to defend Yitzhak Rabin against extremism. It could be doing a great deal more today to prevent the murder of Ariel Sharon.

Jeffrey Goldberg is a staff writer for The New Yorker.