Barely a week goes by without news of some act of violence by Jewish settlers against Palestinians in the occupied West Bank. By any definition, what settlers and other religious activists do to Palestinians is terrorism. But it goes unpunished.

Time and again, Muslim graves and mosques are desecrated, harvests torched, sheep rustled, cars stoned and damaged, homes and shops forcibly occupied. Palestinians are chased off their own land by gunfire. Just last week, settlers cut down 300 olive trees.

The settlers have a new and brutal policy. They have declared that, for every attempt by the authorities to rein them in, they will exact a price in violence against the Palestinians — a "price tag," they call it.

In the Arab world, Islamic extremists such as al-Qaida are pursued, jailed or killed. Two of Al-Qaida’s top leaders were killed in Iraq this week. In Israel, Prime Minister Binyamin Netanyahu has no wish or will to confront his home grown terrorists. Indeed, representatives of the religious settlers sit in his government.

In the Arab world, militants who fight to create an Islamic state are generally considered the enemy. In Israel, the armed underground movement which aims to create a Torah state is treated with kid gloves. The government dares not confront it — or is secretly complicit with it.

Unless Israel’s fanatical settlers — both religious-nationalist and ultra-orthodox — are confronted, and their messianic ambitions tamed, there will be no peace in the Middle East. This means halting and reversing a powerful trend in Israeli society — and in Israel’s armed forces, where the extremists are well-entrenched and, by all accounts, are steadily gaining ground. This is the essential precondition for any serious peace negotiations. But can it be done? Or is the region doomed to suffer more violence?

In a joint article in the Washington Post on 11 April, two prominent American political figures — Zbigniew Brzezinski, President Jimmy Carter’s national security adviser and Stephen Solarz, a former U.S. congressman for New York — urged Obama to go to the region himself on a "journey of peace" and, in a series of speeches in Jerusalem and Ramallah, urge Israelis and Palestinians to start serious negotiations. Such a dramatic move, they argued, could break the logjam.

But it will take more than speeches by Obama, however eloquent they might be, to persuade Israel’s fanatics to change course. Nothing short of real pressure would do the job — such as an American threat to withdraw from Israel its diplomatic support, weapons supply and lavish funding. But such is Israeli influence in the U.S. Congress, in Washington think-tanks and the mainstream American press that nothing is less likely.

There has been much speculation in recent weeks that U.S. President Barack Obama, impatient with the current stalemate, may be about to launch his own peace plan. He has made clear that a settlement of the Arab-Israeli conflict is a vital American interest. The clear suggestion is that he will use American muscle to persuade both the Arabs and the Israelis to negotiate on the basis of his plan. Netanyahu has already publicly rejected any hint of an "imposed peace." The question, therefore, is how much presidential muscle can Obama actually use. He has already been put on notice by the Israeli lobby, and by leading Jewish figures such as Ronald Lauder, president of the World Jewish Congress, not to put pressure on Israel.

A recent publication, Israel’s Religious Right and the Question of Settlements by the International Crisis Group (www.crisisgroup.org), outlines the extent of the danger which Israel’s messianic terrorists pose to the peace process. The picture is not encouraging.

The ICG reports that tens of thousands of religious Zionists inhabit illegal settlements east of the separation barrier on the West Bank. Thousands more "hilltop youth" occupy armed outposts deep in Palestinian territory. These settlements and outposts operate some 200 paramilitary squads, armed with automatic weapons (and "the best telescopic sights on the market") and even armoured vehicles. They perpetrate violence against the Palestinians and are ready to defy any attempt by the state to stop them.

Observers predict that an even larger and better-armed force, prepared for group action, could emerge if the government dared to remove an outpost, or curtail the settlers’ thuggery in any way.

Ultra-orthodox and national-religious politicians hold over a fifth of Knesset seats, representing some forty per cent — 26 out of 65 parliamentarians — of Netanyahu’s ruling coalition. They control the housing ministry and the Israel Land Administration, which manages state lands. These Greater Israel ideologues suffered a "messianic shock" when the then Prime Minister Ariel Sharon dismantled the Gaza settlements in 2005. The move challenged their confidence in the state and reinforced their determination never to allow the evacuation of Jews to happen again. They are adamantly opposed to any further withdrawals and to negotiations with the Palestinians.

Some national-religious rabbis go so far as to endorse the rabbinical license for a Jew to kill any Jew who relinquishes the Land of Israel to non-Jews — an interpretation which Yigal Amir used to justify his assassination of Prime Minister Itzhak Rabin in 1995.

The Israeli armed forces have been deeply penetrated by religious extremists. Army Torah colleges, in which conscripts mix military service with religious study over a five-year period, have mushroomed in Israel. Nearly half are on the West Bank, graduating thousands of soldiers. National-religious officers are estimated to account for up to 30 per cent of the Israeli officer corps, with a particularly high concentration in combat units. One source told the International Crisis Group that "in a few years, religious soldiers will make up the majority of brigade commanders in all areas — from F-16 fighter jets to submarines."

A senior officer, of national-religious beliefs, explained:

"An order to withdraw [from the West Bank] will destroy Israel. It will split the army and turn part of it against the state. I would rather give up Tel Aviv than Hebron. We are not just a state of Jews, or a Jewish majority, but a Jewish state defending the land that is promised to us by the Bible, by God. It is Jewish land. I will defend Jewish land by all legitimate means — and if that isn’t enough — by illegitimate means. It can be by force."

What does the ICG recommend to check this dangerous descent into the abyss? Demarcating an agreed Israeli-Palestinian border, rather than focussing efforts on a settlement freeze; announcing a compensation package to persuade some settlers to leave the West Bank voluntarily; reaching out to religious parties, such as Shas and Agudat Israel, and including them in the diplomatic process; insisting that Israeli security agencies and courts investigate and prosecute cases of anti-Palestinian violence. None of this seems enough.

It is surely time for Israel’s secular majority to wake up to the danger or risk finding itself living in a state run by messianic terrorists, shunned by the whole world.

Patrick Seale is a leading British writer on the Middle East. His latest book is The Struggle for Arab Independence: Riad el-Solh and the Makers of the Modern Middle East (Cambridge University Press).