The settlements: How large they loom in the world of international politics and diplomacy. Yet how small, how vulnerable these “facts on the ground” are in reality.

Unlike their counterparts, the Palestinian refugee camps, they are rarely depicted sympathetically; settlers are punished for not playing the role of victims. When a Palestinian from a camp in Gaza becomes a suicide bomber, his destructive response to his fate is seen as tragic; a Jew who responds constructively to his predicament by building a settlement is demonized.

The principal obstacle to peace in the Middle East in the eyes of the global press and broadcast is not the Arab terrorist, but the Jewish settler. To paraphrase Churchill: Never in the history of human conflict has so much blame been heaped by so many on the heads of so few.

Gershom Gorenberg is certainly not an apologist for the settlers.Though he is interested in their motives and their individual stories, his narrative implies that he shares the view that it would have been better for Israel and for humanity as a whole if they had never existed.

The main point of his new book, “The Accidental Empire: Israel and the Birth of the Settlements, 1967-1977” (Times Books, 454 pages, $30), however, is to disprove the myth that the settlements are solely the creation and obsession of the religious right. All too few now defend them, even in Israel. So it is a myth that suits many people. But it is a myth all the same.

Mr. Gorenberg’s account of the decade after the Six-Day War proves beyond doubt that the settlements would never have come into being without the encouragement of mainstream secular Zionists, and especially the leaders of the Labor Party, which dominated Israeli politics for three decades from the foundation of the Jewish state until the emergence of a strong right-of-center coalition in the shape of Likud.

In other words, the policy of establishing Jewish settlements in the territories occupied in 1967 rests squarely on the shoulders of the Israeli left, which is now eager to denounce that policy as a disastrous mistake. Shimon Peres was at least as much a patriarch of the settlers as Menachem Begin or Ariel Sharon, for it was Defense Minister Peres who refused to deport them in the first, decisive confrontation in 1975.

Nor is it the case that the Labor leaders did not know what risks they were taking. Mr. Gorenberg has unearthed a secret memo to Prime Minister Eshkol from the legal counsel to the foreign ministry, written in September 1967, which states that the settlements would contravene the Fourth Geneva Convention. As soon as Israel occupied the territories, its leaders knew that letting settlers move in would give the Arabs a powerful propaganda weapon.

I don’t care for the book’s title, “The Accidental Empire,” because it is misleading – and even mischievous – to call a few square miles of land, including some of the most inhospitable terrain on earth, an “empire.”The population of all the settlements put together, even if you include annexed East Jerusalem, is still smaller than that of Washington, D.C. Even if they had achieved their goal of spreading all over the biblical territories of Eretz Israel, the settlers would not control more than a tiny fraction of the land that Israel’s Arab neighbors have at their disposal.

Yet Mr. Gorenberg’s title is not entirely wrong. It is true that Israel acquired its settlements partly by design, but also partly by accident. Of the English, the Victorian historian Sir John Seeley claimed that they “conquered and peopled half the world in a fit of absence of mind.” Much the same might be said of the Israeli settlements.

Only in this case, absence of mind was not just on Israel’s part. It was no less characteristic of successive American administrations. For the 1970s was a period when both the White House and the Kremlin saw the Middle East as a stage on which superpowers could legitimately fight proxy wars.

Henry Kissinger was denounced by the settlers’ organization Gush Emunim for his insistence that Israel would have to renounce Sinai to make peace with Egypt. But he was also the first American statesman to tell the Arab leaders, as early as the immediate aftermath of the 1973 Yom Kippur War, that “Israel would not give up a single settlement for the disengagement.” He added that he “had told Israeli leaders I would not press them to do so.” Mr. Kissinger can be credited for the fact that the first settlement on the West Bank, at Sebastia, was allowed to stay.

The Ford administration, like some in the Israeli foreign ministry, regarded the settlers’ presence in occupied territory as illegal, but it saw the issue as a minor one and never used its leverage to force Prime Minister Rabin to evict the settlers. The State Department even asked the Israelis to keep press coverage of the settlers to a minimum. The American decision to turn a blind eye to the settlements was a necessary, though not a sufficient, condition for them to become a tool of Israeli policy.

The author’s research has taken him into numerous hitherto unopened state and private archives, both in Israel and America, and he has interviewed the key surviving players. His perspective may be too liberal and secularist for readers who are sympathetic to the settlers.

The Yom Kippur War, in the middle of the period covered by Mr. Gorenberg, was a shattering blow to Israeli self-confidence – but it also created the apocalyptic atmosphere in which a determined minority could mobilize support.

The second event that acted as a catalyst for the settler movement was the United Nations General Assembly’s resolution in November 1975 proclaiming, “Zionism is a form of racism.” That outrageous slur was the last straw, completing Israel’s sense of diplomatic isolation.

It is no wonder that many Jews despaired of an international community that had not lifted a finger to help when the Arabs had attempted to stifle Israel at birth in 1948. Despite memories of the Holocaust and decades of unremitting Arab hostility, the United Nations had turned against the Jewish state that it had created. Since the mid-1970s Israel has been led by old men in a hurry. In their youth they had been Zionist pioneers of left and right, secular and religious. Now they identified with the settlers, who reminded them of an earlier, more heroic era.

When Mr. Sharon finally turned against the Gaza settlers two years ago, sacrificing their dreams for the harsh reality of his disengagement plan, they woke up to find that their only friends were on the extreme religious right. The withdrawal from Gaza was accomplished without the traumatic effect on national morale for which the settlers had hoped.

Now the kaleidoscope has shifted again. Mr. Sharon, Israel’s General de Gaulle, was abruptly felled by a stroke, while across the Fence, Hamas seized power in the putative Palestinian state. The West Bank settlements may yet live to fight another day.

Mr. Johnson’s “London Letter” appears Thursdays in The New York Sun.