You can’t discount an argument on the grounds that you suspect some of its proponents of ignoble motives for making it. It is almost certainly the case that some critics of the state of Israel are motivated by anti-Semitism, but that doesn’t invalidate all criticism of Israeli policy or actions. The occupation of the West Bank is illegal whether you're anti-Semitic or not.

Defenders of Israel sometimes ask – the international relations equivalent of a drunk driver telling the police to go after real criminals – why the left is so focused on Israel’s wrongdoings, rather than the often far worse crimes of other states. But the answer probably has less to do with anti-Semitism than the fact that, of the $5.7 billion the United States spends each year on foreign military financing, $3 billion goes to Israel.

You can’t police the way people think, only what they do, which may sometimes include what they say. There are two separate, if loosely connected problems facing the Labour Party in the fall-out from Naz Shah’s once throwaway, now notorious Facebook post. In 2014, before she was elected MP for Bradford West, and before Jeremy Corbyn was elected Labour leader, she shared an image of Israel’s outline superimposed on a map of the United States – you can see it here on Norman Finkelstein’s blog, which may or may not be where Shah took it from – with the comment: ‘Problem solved.’ How wrong she was.

Labour’s first problem is that a small number of its members and elected representatives are given to making anti-Semitic remarks on social media. Five councillors, including a former mayor of Blackburn, have been suspended this week. To put the numbers in context: Labour has 228 MPs, one of whom (0.4 per cent) has been suspended for suspected anti-Semitism; more than 7000 councillors, of whom 0.07 per cent have been suspended; and more than 388,000 members, of whom 50 (0.012 per cent) have been ‘secretly suspended’, the Telegraphreported, ‘as officials struggle to cope with the crisis engulfing the party’.

Labour’s second problem, gestured at by the measured tones of that Telegraph piece, is its self-destructive infighting, which is dominating political coverage not only in the overtly Tory press but also on the BBC, at a time when Labour should be capitalising on divisions in the Conservative Party. Ken Livingstone (also suspended), who has done more than any other individual in the party to make a bad situation a lot worse, is completely wrong about Hitler’s alleged Zionism (and such ill-judged comparisons between Israel and the Nazis do absolutely nothing to help the Palestinian cause), and probably wrong to say there are no anti-Semites in the Labour Party, but he had a point when he said that the scandal was the fault of ‘embittered old Blairites bringing it up’.

Shah’s apology, the suspensions, and Corbyn’s announcement on Friday that Shami Chakrabarti would lead an independent inquiry into anti-Semitism in the Labour Party, suggest that the leadership is doing its best to address the first problem. But the second may well be intractable. Corbyn doesn’t have the authority to silence the embittered old (and not so old) Blairites, and it seems that they would rather bring Corbyn down, at any cost, than try to win any elections under his leadership. (I’ve long suspected that one of the reasons for their hostility to Corbyn, and to Labour’s recent shift to the left, is the danger of its exposing the hollowness of the entire New Labour project: it’s still widely accepted that Labour won the 1997 election because of Blair’s ‘reforms’, when the truth is that the Tories were doomed to lose, and it made little difference who the Labour leader was.)

The one place Labour has been expected to do well tomorrow is London. Sadiq Khan still leads Zac Goldsmith by a comfortable margin in the opinion polls but, as Khan says, the polls have been wrong before, and Livingstone’s recent interventions have made his job a lot harder. You could be forgiven for thinking that Livingstone – not entirely unlike the Blairites – has long been committed to a narcissistic project of preventing anyone else from the Labour Party ever being elected mayor of London. His scuppering of Khan follows his idiotic insistence on standing against Boris Johnson in 2012, only four years after Johnson had unseated him. The contest was close, and a different Labour candidate might have won.

Khan has been doing his best to distance himself from Livingstone as polling day approaches. He has said, quite rightly, that Labour needs to take anti-Semitism as seriously as it does other forms of racism. But the Labour Party is far from the only institution in Britain that’s guilty either of racism, or of thinking that some forms of racism are worse than others.

In March, the Tories distributed leaflets saying that Goldsmith was 'standing up for the British Indian community', while Khan (whose parents emigrated to Britain from Pakistan) 'supports a wealth tax on family jewellery'. In the Mail on Sunday at the weekend, Goldsmith wrote a ‘passionate plea’ not ‘to hand the world’s greatest city to a Labour Party that thinks terrorists are its friends’. The piece was illustrated with a photograph of the number 30 bus blown up in Tavistock Square on 7 July 2005. Goldsmith has since said he thought the headline and photograph were 'a mistake', but he 'stands by every single word' of the article (e.g. 'if Labour wins on Thursday, we will have handed control of the Met, and with it control over national counter-terrorism policy, to a party whose candidate and current leadership have, whether intentionally or not, repeatedly legitimised those with extremist views').

According to the Home Office statistical bulletin on hate crime in England and Wales last year, ‘Muslim adults were the most likely to be a victim of religiously motivated hate crime.’ There is no sign that Zac Goldsmith is in any danger of being suspended by the Conservative Party.

Read more in the London Review of Books

Judith Butler: No, it’s not anti-Semitic · 21 August 2003

Jacqueline Rose: Dreyfus in Our Times · 10 June 2010

Ian Jack: Ken Livingstone · 10 May 2012