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In a year brimming with profoundly symbolic centennials, Thursday marks perhaps the most politically fraught one. Israeli Prime Minister Benjamin Netanyahu will appear in London alongside his British counterpart, Theresa May, to commemorate the 100th anniversary of the Balfour Declaration, a 67-word missive from Britain’s then-foreign secretary expressing his government's support for a Jewish homeland in Palestine.

The Nov. 2, 1917, public letter was written by Lord Arthur Balfour to Baron Walter Rothschild, the head of the British wing of the influential European Jewish banking family. Balfour articulated the British desire for the establishment of “a national home for the Jewish people” and promised that his government would “facilitate the achievement of this object.” It would take three further decades — and a great deal more politicking and bloodshed — before Israel declared independence in 1948.

But the Balfour Declaration is held up as a seminal event, the first formal utterance of the modern Israeli state’s right to exist (though some historians quibble that a “national home” is not the same thing as a state). For that reason, it is also bitterly regarded by many Palestinians as the first instrument of their dispossession. In 1917, Jews made up less than 10 percent of Palestine’s population — a century later, they are now the majority, while millions of Palestinians live in exile or in refugee camps. Protests are planned in the Palestinian territories to mark the centennial.

For many Israelis, the centennial is something to celebrate — especially on British soil. It was partially thanks to the efforts of a coterie of Britain-based Zionists, particularly Russian-born chemist Chaim Weizmann, that Balfour and his government were persuaded to eventually seek a colonial mandate for Palestine as Western powers carved up the crumbling Ottoman Empire. “I am proud of Britain’s part in creating Israel,” wrote British Foreign Secretary Boris Johnson in a column for the Sunday Telegraph.

But the occasion is a bit more awkward for the British prime minister, who is expected to spar with Netanyahu over the Israeli leader’s hawkish line on the Iran nuclear deal. Meanwhile, May’s chief opponent, Labour leader Jeremy Corbyn, is known for his pro-Palestinian sympathies and has opted against attending the Thursday dinner commemorating the Balfour Declaration. His hesitance is not unique: A recent survey found that only 17 percent of Britons hold favorable views of Israel.

Across Europe, there’s a great deal of support for the recognition of an independent Palestinian state amid anger at the policies of Netanyahu’s right-wing government, which is expanding Israeli settlements in the West Bank while maintaining a stifling military occupation over the Palestinian territories. Critics point to a line in Balfour’s letter that “nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine” — a stipulation that doesn’t seem to have been followed amid the conflicts and upheavals that came after.

“The Balfour declaration is not something to be celebrated — certainly not while one of the peoples affected continues to suffer such injustice,” wrote Palestinian Authority president Mahmoud Abbas in a column published this week in the Guardian. “The creation of a homeland for one people resulted in the dispossession and continuing persecution of another — now a deep imbalance between occupier and occupied. The balance must be redressed, and Britain bears a great deal of responsibility in leading the way. Celebrations must wait for the day when everyone in this land has freedom, dignity and equality.”

Israeli officials liken the Palestinian refusal to accept the declaration as evidence of their broader rejection of Israel. “The vehement Palestinian Arab opposition to the Balfour Declaration was and has remained rooted in the anti-historical view that Jews were aliens, with no connection to the land and no right of any kind to live there as a people,” wrote top Israeli diplomat Yuval Rotem. “This spawned an Arab exclusivism and sense of supremacy, which continues to drive the Arab-Israel conflict to this day.”

Of course, the motives driving Balfour, an influential Conservative statesman who briefly served as prime minister, had as much to do with geopolitics as any abiding sympathy for the Zionist plight. On an earlier visit to the region, he described Palestine as a “dolorous country on the whole” and Jerusalem as a “miserable ghetto, derelict and without dignity.”

Just days before issuing the declaration, Balfour said at a cabinet meeting that appealing to Jewish nationalism would serve as “extremely useful propaganda both in Russia and in America” — two countries with significant Jewish populations and whose contributions were necessary to winning World War I. After the declaration was announced, British leaflets were dropped over Jewish communities in German and Austrian territory pointing to the good deeds done for the “people of Israel.” (In 1917, the only Jew in Britain's cabinet, Edwin Montagu, strenuously opposed Zionism, which he said was a "mischievous political creed" that would endanger the Jewish presence in Europe.)

The Balfour Declaration was just one piece in a series of British diplomatic efforts that helped shape the map of the modern Middle East. In 1916, Britain had already agreed in secret with France and Russia to a division of the Ottoman possessions that saw Palestine designated under joint “international control.” A year later, with the Bolshevik Revolution upending some of these plans, Britain sought to consolidate a buffer between a French-dominated Levant and their colonial concerns in Egypt — and so a mandate for Palestine looked more and more appealing. Zionists, buoyed by the British support, lobbied for Palestine to be placed under British rule, which it eventually was.

As for Lord Roderick Balfour, the great-great-nephew of the declaration’s architect, he sees flaws still unaddressed in his ancestor’s famous act.

“I have major reservations,” he recently told reporters. “There is this sentence in the declaration, ‘Nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine.’ That’s pretty clear. Well, that’s not being adhered to. That has somehow got to be rectified.”

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