One hundred years ago — on November 2, 1917 — the British Foreign Secretary, Arthur Balfour, issued a letter to the British Jewish leader, Lord Walter Rothschild, pledging British support for “a national home for the Jewish people” in Palestine. The Balfour Declaration was a milestone in the Zionist effort to re-create the Jewish home in the land where, nearly two millennia earlier, it had existed for centuries.

By 1922, the Balfour Declaration had become an established part of international law: endorsed after World War I by the Allies at their San Remo Conference; included in the 1920 peace treaty signed by Turkey’s Sultan Mehmet VI; and incorporated in the League of Nations Mandate for Palestine in 1922, which expressly recognized “the historical connection of the Jewish people with Palestine” and their basis “for reconstituting their national home.”

After receiving the League of Nations Mandate, Britain split off the eastern portion of Palestine — known as “Transjordan” — and recognized the Arab emir, Abdullah, as its ruler. Strife between the Arab and Jewish communities in western Palestine led Britain in 1937 to propose a two-state solution: most of western Palestine would also become an Arab state, with a minuscule Jewish state in the remainder.

The Arabs rejected the 1937 partition proposal and also the 1947 United Nations two-state resolution, in favor of a war against the Jews. After Israel won, the Arabs rejected three additional two-state proposals: the 2000 Israeli offer at Camp David, the Clinton Parameters of 2000-2001, and the 2008 offer at the end of the Bush administration’s “Annapolis Process.” It seems safe to say that no people in history have been offered a state — and rejected it — more times than the Palestinian Arabs.

In 2009, Benjamin Netanyahu became the fourth Israeli prime minister to endorse the two-state solution (after Ehud Barak, Ariel Sharon, and Ehud Olmert), as long as the Palestinians recognize Israel as a Jewish state. Yet the Palestinian president, Mahmoud Abbas, soon to start the 14th year of his four-year term, has repeatedly said he will “never” recognize a Jewish state in any part of Palestine and repeatedly demands that Britain “apologize” for the Balfour Declaration, which he asserts is the original cause of the conflict.

Therein lies the crux of the continuing Israeli-Palestinian dispute.

Peace processors used to believe that Israeli-Palestinian peace was a 1967 issue, negotiating suitable borders; or perhaps a 1948 issue, dealing with the refugees from the Arab war against Israel. It is now clear that it is a 1917 issue – the rejection by the Palestinian Arabs of any Jewish sovereignty anywhere in the ancestral homeland of the Jews. It is, in the words of Ron Dermer, currently Israel’s ambassador to America, the “core issue”: the Palestinians will not even agree that the goal of the “peace process” is “two states for two peoples.”

Instead of referring to “two states for two peoples,” the Palestinians always frame the goal of the process as ending “the occupation that began in 1967.” The reason they invariably add the last four words to that formulation is that they believe there is also another occupation that they want eventually to end as well: “the occupation that began in 1948.” That is the reason they say they can “never” give up an asserted “right of return.” To do so would be to recognize Israel as a Jewish state.

President Trump’s administration is currently deliberating on a new peace process, despite the failures of Presidents Clinton, Bush, and Obama over nearly three decades. A key to whether there would be any chance for success is whether the Palestinians will agree at the outset that the goal is “two states for two peoples.” One hundred years after the Balfour Declaration, and 95 years after the international community endorsed it, the Palestinians are still fighting the recognition of any Jewish sovereignty. They want a Palestinian state, but not at the cost of recognizing a Jewish one.

Mr. Richman is the author of “Racing Against History: The 1940 Campaign for a Jewish Army to Fight Hitler,” which Encounter Books is bringing out in January.