In May of this year, Secretary of State Hillary Clinton made it clear that the Obama administration would have little tolerance for the growth of existing settlements. After Obama's position was made public, extremist settlers rapidly erected new buildings and repaired outposts. In one location they built a wooden structure they named an "Obama hut." Around the same time, an Israeli newspaper reported that the senior Israeli army officer in the West Bank had received threatening letters, apparently from radicals trying to dissuade the military from evicting settlers from their homes.

There are now more than a quarter of a million Jewish settlers living among almost 2.5 million Palestinians in the West Bank—and many of the radicals resisting Obama's wishes are American. The approximately 100,000 U.S. immigrants in the West Bank and Israel have been influential from the beginning of the movement, and many of them have been among the most extreme of the pioneers: Kahane founded a political party that was deemed racist and banned from the Knesset before he was assassinated in Manhattan in 1990; Brooklyn-born Baruch Goldstein shot dead 29 Palestinians in Hebron in 1994; and a group of settlers in Hebron, whose spokesman is New Jersey–born David Wilder, was involved in a violent confrontation with the Israeli military last year.

While Kahane's original followers and other American extremists continue to face arrest and monitoring by Israeli security services, it is the young people—many of them, like Ephraim Khantsis, American—in the settler movement who are now the Israeli government's primary concern. This new generation of hard-liners differs from the previous one in a crucial way—its members are profoundly alienated from the secular Israeli state.

This increasing radicalization is a response to the forced removal of Jews from West Bank settlements that the Israeli government considers obstacles to peace. In August 2005, the government of Ariel Sharon, once the great champion of the settlement movement, evacuated thousands of people from the Gaza Strip. The settlers generally did not use violence against the soldiers and police officers who came to evict them, tearfully pleading with—and even hugging—them instead. But that strategy failed. Some extremist settlers said they would never leave so easily again. True to their word, they put up a fight when the army tried to evacuate a settlement at Amona, in the West Bank, in February 2006—more than 300 people were injured.

Nowadays the talk is that the next evacuation will lead to even more violence. "I can tell you one thing," says Yedidya Slonim, a 16-year-old Australian immigrant who lives in a sizable cave on a hill in the West Bank that functions as an illegal outpost called Shvut Ami. "What happened over there when the people hugged the policemen—that ain't going to happen."

"A lot of kids have got no authority, just them and God out there on the hills," says Yekutiel Ben Yaakov, 50, formerly of Queens, New York, who now lives in Kfar Tapuach and has provided guard dogs for some of the young extremists who set up illegal hilltop camps.