Nearly a year in advance of the centenary of the Balfour Declaration, a campaign is underway to wring from Britain an apology for the pledge that set the stage for the reconstitution of a Jewish state in the land of Israel. The pledge was made on November 2, 1917, in a letter to Baron Rothschild from Britain’s foreign secretary, Arthur James Balfour. Signaling that Zionism would be among the causes rewarded in World War I, the letter proved to be one of the most consequential three-paragraph notes in history.

It was penned 11 years after Balfour’s first meeting with the Zionist Chaim Weizmann, who would go on to become Israel’s first president. They met in 1906 at a hotel in Piccadilly, where Balfour, then running for parliament, was headquartering and where they fell into a conversation about Herzl and the Uganda Plan. “Mr. Balfour,” Weizmann said, as he recounted the story in his memoirs, “supposing I were to offer you Paris instead of London, would you take it?” Balfour replied: “But, Dr. Weizmann, we have London.”

“That is true,” Weizmann responded. “But we had Jerusalem when London was a marsh.” Balfour leaned back and eyed the chemist. Then he said: “Are there many Jews who think like you?” Weizmann famously answered: “I believe I speak the mind of millions . . .” It was an astonishing meeting of the minds, though it would take eleven years, the elevation of Balfour to high office, and a world war to bring forth the letter that, as part of Britain’s geopolitical maneuvering, would begin to change the world.

The nub of the letter said: “His Majesty’s government view with favour the establishment in Palestine of a national home for the Jewish people, and will use their best endeavours to facilitate the achievement of this object, it being clearly understood that nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine, or the rights and political status enjoyed by Jews in any other country.” The letter described that statement as a “declaration of sympathy with Jewish Zionist aspirations.”

It would be a mistake to make too much of Balfour’s note. In a number of ways the text fell short of Zionist hopes (“the” national Jewish home would have been better than “a” national Jewish home, for example, and “national Jewish home” was not as ideal as “Jewish state” etc.). Plus, too, the World War was still in progress. The League of Nations had not been brought fully into being, and Britain had not been given the mandatory power over what was then called Palestine. But the letter was not nothing.

The campaign for an apology is unlikely to prevail in Britain’s parliament, judging by the discussion last month in the Commons. It is, though, underscoring the rejectionist nature of the Palestinian Arab agitation. This was marked the other day in Jerusalem by Prime Minister Netanyahyu, who noted that the call for an apology for the Balfour declaration is — as the premier’s remarks are paraphrased by Breitbart News — driven “not by territorial dispute but by the very existence of the Jewish state.”

Mr. Netanyahu is quoted by Breitbart as saying the demand for an apology is “very revealing about the true source of this enduring conflict.” It is “not about territory, even though that’s an issue. It’s not about settlements, even though that’s an issue. It’s not the issue. It was never and is still not about the Palestinian state. It was always about the Jewish state,” which illuminates the logic of Mr. Netanyahu’s hard line. Or as he puts it: “The fact there was a challenge to the Balfour declaration 100 years later tells us we haven’t come very far.”

We wouldn’t want the premier to get too down on the point. The pending centenary is a chance to savor the dignified and statesmanlike way in which modern Israel was brought into being in the decades since Herzl walked out of the Dreyfus trial and sat down in a hotel room to write “Der Judenstaat.” It may have come occasionally to arms, but what masterful diplomacy preceded the revolt of 1948. And what a well of sympathy that diplomacy discovered among certain leaders of the Empire, something to be celebrated without apology at the centenary of Balfour.