“JEWS have no better friends in this country than the Labour Party.” So said the Jewish Chronicle in 1920. Almost a century on the newspaper’s tone has changed. When it emerged that Labour’s leader, Jeremy Corbyn, was a member of a private Facebook group littered with anti-Semitic abuse, the Jewish Chronicle’s editor penned a note of despair. “We run far, far less about [Mr Corbyn] and Labour’s anti-Semitism issue than the story probably deserves, precisely to avoid it dominating the paper.”

There has certainly been plenty that could fill its pages. Mr Corbyn’s “unwitting” membership of the Facebook group was the latest anti-Semitism row to embroil the party since he became leader in 2015. Earlier this month, the race to become general secretary was marred by anti-Semitic abuse of Jon Lansman, founder of the left-wing pressure group Momentum. A row over dealing with party members suspended for alleged anti-Semitism has rumbled for months. In 2016 Ken Livingstone, a former mayor of London, was kicked out of the party for suggesting that Adolf Hitler supported Zionism “before he went mad and ended up killing 6m Jews”.

Not everyone is willing to accept that Labour has a problem. Len McCluskey, the boss of Unite, Britain’s biggest union and a strong supporter of Mr Corbyn, dismissed allegations of anti-Semitism as “mood music” and an attempt to undermine the leader. Even when senior figures admit the party’s troubles, caveats soon follow. Andrew Murray, one of Mr Corbyn’s advisers, told an audience of activists and left-wing hangers-on that “there is anti-Semitism in the Labour Party”. But he added that such allegations, while justified, were also meant to “destabilise the party and this needs to be challenged as well”. Instead, he went on, what was needed was a lesson in the differences between anti-Semitism and anti-Zionism.

Israel and Palestine loom large in the party’s tortuous relationship with Britain’s Jews. Mr Corbyn has dedicated much of his career to fighting for the rights of Palestinians. This has sometimes brought him into proximity with people who hold unsavoury views of Jews. While Mr Corbyn has never himself been accused of anti-Semitism, he has shared platforms—and Facebook groups—with those who have.

The struggle to disentangle anti-Semitism from fraught discussions over the Middle East is not unique to Labour, points out David Feldman, a historian of anti-Semitism at Birkbeck, University of London. Where parts of the left sometimes fail “is in recognising anti-Semitism when it is in front of them”, he adds. “The commonplace idea that racism is power can leave people poorly equipped to identify racism when it is directed at Jews in Britain.” This blind spot is particularly egregious in a party that prides itself on its anti-racism, says Richard Angell, who runs Progress, a centrist Labour caucus. “We would not tolerate it for any other group,” he says.

Internal rows about anti-Semitism have already hit the party electorally. While Labour made gains across London in last June’s general election, Labour struggled in the “bagel belt”—a group of constituencies in the north-west of the city with large Jewish populations. Data are sketchy, but a poll taken just before the election suggested that only 13% of Jews intended to vote Labour. Some 77% backed the Conservatives.

Labour’s attempts to solve its problem have been patchy. A report into anti-Semitism in the party by Shami Chakrabarti, a human-rights lawyer turned Labour peer, suggested such reforms as banning the term “Zio” and clearer disciplinary proceedings. Although it was derided as a whitewash by some, John Mann, a Labour MP who leads the all-party parliamentary group against anti-Semitism, welcomed the report. His only demand was that the party hurry up and implement it. Efforts to root out those accused of anti-Semitic slurs online have been slow and attracted unhelpful cries of witch hunts from a minority. A party should not be judged by its cranks, but by how it handles them. On this, Labour still falls short.