Last January the wretched and dispossessed in the slums of Gaza helped elect Hamas, and were duly told by Blair, as well as the Americans, that this was an unacceptable way to vote - a curious reflection on the much-trumpeted project of "democratising the Middle East". Apart from the question of recognising Israel, Hamas stands condemned for espousing terrorist violence.

There have indeed been outrageous and indefensible killings of Israeli civilians, but even that raises more questions than it answers. It is a platitude to say that one man's terrorist is another man's freedom fighter. Palestinians will point out that Israeli state violence has always more than matched that of its opponents - notably in the numbers of civilians killed - and they could point out also that this dates from before the creation of the state of Israel.

An anniversary in July was a reminder of that, though it passed unnoticed here. And it has also been barely remarked that Israel has today the purest Revisionist government in its history. Ehud Olmert, the prime minister, has been described as "one of Likud's princes from a prominent Revisionist family", which makes Tzipi Livni, his photogenic foreign minister, a princess.

In an interview with the Spiegel, the German magazine, she said that as a girl "All I ever heard about was that we Jews have the right to a state on both sides of the Jordan". Her father's grave bears the old map of that Greater Israel of Revisionist dreams, and she is one of the few prominent Israelis who can still quote the works of Vladimir Jabotinsky, the brilliant and charismatic man who founded the political tradition from which the groups called Betar, Irgun Zvei Leumi, Herut, Likud and now Kadima descend: a tradition to which she and Olmert belong by birth.

After the 1917 Balfour declaration had promised a Jewish homeland ("it being clearly understood that nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine"), the British became rulers of Palestine under the somewhat dubious guise of a League of Nations mandate, and violence between Jews and Arabs erupted at once.

In the 1920s Jabotinsky created the Revisionist Zionist movement, defiantly nationalistic and militaristic, with an aim of admirable clarity: "The revival of the Jewish state with a Jewish majority on both sides of the Jordan." For Jabotinsky, Zionism was a psychological as well as political project. In an essay entitled Against Excessive Apology, he told the Jews to stop cringing and tell the goyim "to go to hell", which Olmert may be said to have taken to heart.

Instead of pretending that Palestine was "a land without people for a people without land", or that the existing inhabitants would welcome the Zionists, Jabotinsky insisted that they would not: "The native population, civilised or uncivilised, have always stubbornly resisted the colonists." It was thus "utterly impossible to obtain the voluntary consent of the Palestine Arabs", and the Zionists must be ready to use force by building an "Iron Wall". His famous phrase has now been interpreted literally by the Israeli government.

Only elements on the far left and some radical Islamists today care to call the Israeli government fascist. And yet, just as the strongest opponents of Zionism a hundred years ago were not antisemites (some of whom rather liked the idea of shipping the Jews off to the east) but other Jews, so in the early years of Revisionism its harshest critics were not gentiles (few of whom knew much about these intestine scissions), but other Zionists. In the 30s, David Ben Gurion, the Labour leader who became Israel's first prime minister, called his antagonist "Vladimir Hitler", and the Zionist leader Chaim Weizmann told the New York lawyer Morris Rothenberg that the Jewish extremists evinced "Hitlerism in its worst possible form". That was, of course, before anyone knew what horrors Hitler would inflict on the Jewish people, but the phrase was startling even then.

By the late 1930s some Revisionists had formed the Irgun, an armed militia committed to driving out the British and dealing with the Palestinian Arabs - by whatever means seemed necessary. "In blood and fire did Judea fall, In blood and fire will Judea rise again," ran one Revisionist song, and the Irgun were as good as those words.

On July 22 1946 they blew up the King David Hotel in Jerusalem, which housed the British headquarters of the military command, killing 91 people, among whom 28 were British, 41 Arab and 17 Jewish. In a ceremony this July, old Irgun hands unveiled a plaque to mark the 60th anniversary. The following year, in reprisal for the execution of Zionists, the Irgun hanged two captured British sergeants, and they habitually attacked Arab civilians, culminating in the bloodshed that accompanied the birth of the state.

We are now meant to be waging a "war on terror", and "terrorist" is a curse supposed to end all argument. But those who once supported the Irgun didn't shirk that word. The playwright and Hollywood screenwriter Ben Hecht, famous in his day as the co-author of the classic newspaper black comedy The Front Page, was also an ardent Revisionist and adherent of the Irgun.

In May 1947 he published an advertisement in New York newspapers saluting the bombers of the King David: "The Jews of America are for you. You are their champions." Every time they "let go with your guns and bombs at British betrayers and invaders of your homeland, the Jews of America make a little holiday in their hearts". Still more striking was Hecht's admiring and intransigent headline above his ad: "Letter to the Terrorists of Palestine".

There is no way of knowing what Jabotinsky would have made of that, since he died in 1940. But he had specifically repudiated the political assassination that Israeli governments have practised in recent decades, and he said that: "It must be hateful for any Jew to think that the rebirth of a Jewish state should ever be linked with such an odious suggestion as the removal of non-Jewish citizens." Such "removal" was just what was practised by the Irgun in 1948, and later by Labour governments that uprooted Palestinian villages.

All of this ought to be a potent memory for Ehud Olmert, who spent his early years in an Irgun camp where his father was one of the leaders, and for Tzipi Livni, whose father ran guns for the Irgun. Mightn't that possibly give them some insight into the other "terrorists of Palestine" who have been tempted by "blood and fire", and who also believe they have the right to a state?

· Geoffrey Wheatcroft is the author of The Controversy of Zion

wheaty@compuserve.com