David Clark, in today’s Guardian, argues that “attempts to brand the left as anti-Jewish because of its support of Palestinian rights only make it harder to tackle genuine racism”.

Ken Livingstone employed low-level racist abuse against a Jew and decided to blow it up into a big story in which he could portray the response as an anti-democratic Zionist witch-hunt.

The Reverend Dr Ken Sizer, leader of the boycott Israel campaign in the Church of England, accused the Chief Rabbi of “crying antisemitism” and used the term “the people in the shadows” to describe those who are worried that his call for disinvestment is “only the first” in a long line of calls for economic, cultural and academic boycotts of Israel.

Israel is often portrayed as an apartheid state that should be boycotted by all right-thinking anti-racist people, as though it was a unique evil in the world.

Clark quotes John Mann, the MP who chairs the Parliamentary Committee Against Anti-Semitism, as saying: “Anti-semitism is back in fashion and can be found on the streets of Islington, Aldershot and Bethnal Green.”

Bethnal Green, not because, as Clark claims, it has a large Muslim population, but because its MP is George Galloway, who thinks that Jews are foreigners in Jerusalem who are raping that city . He also thinks that the British newspapers are all controlled by “Zionism”.

Galloways’s colleague in Respect, Yvonne Ridley calls Israel “a vile little state” “festering in the Middle East” and claims that all the mainstream parties are “riddled with Zionists”. “If there was any Zionism in the Respect Party they would be hunted down and kicked out,” she tells us.

Respect is pushing for power in Tower Hamlets on the lead policy of twinning it with Jenin, the Palestinian town in the West Bank.

The President of Iran is currently trying to attain nuclear weapons, thinks that Israel should be wiped off the map, is organising a Holocaust denial fest in Tehran, and finances groups in Palestine that aim to kill Israeli civilians.

Sue Blackwell, a leader of the boycott Israel movement in academia tells us that “...increasingly these days I find myself having acrimonious exchanges, usually by email, with people whose messages start by expressing their support for my stand on Palestine and then continue with ‘I think you ought to read this.’ … ‘This’ often consists of the Protocols of the Elders of Zion.”

The elected representatives of the Palestinian people, Hamas, say in their founding covenant that Israel has no right to exist, that Jews should be killed, that Jews amassed a huge amount of money and used that wealth to control world media, news agencies, the press, publishing houses, broadcasting stations; they tell us that Jews were behind the French Revolution and the Communist revolutions, Freemasonary and Rotary Clubs, World War I, World War II and the UN Security Council.

Clare Short brings the Jew-hating organisation Hizb ut Tahrir to Parliament so that they can show MPs that they don’t hate Jews ; she also thinks that "US backing for Israeli policies of expansion of the Israeli state and oppression of the Palestinian people is the major cause of bitter division and violence in the world". Ken Livingstone fetes the Jew-hater Yusuf al-Qaradawi at City Hall and hails him as an “honoured guest”.

David Clark’s response to this barrage of anti-Israel enthusiasm, demonization of Israel and antisemitism, is to fall back on a number of tired and clichéd evasions. It is not the fact that there are so many on the left that seek to make the visceral loathing of Israel respectable that annoys Clark. What annoys Clark is that there are others prepared to fight back. What Clark can’t bear is that increasingly, Jews and anti-racists are not prepared to sit silently by and allow these Jew-loathing narratives to be woven into the fabric of left commonsense.

The truth is that there have always been pro-totalitarian and antisemitic currents on the left but that these currents were always militantly opposed by others on the left who were anti-racist and who took liberty seriously. Karl Marx thundered against the ultra-left antisemitic rubbish of Bruno Bauer, when Bauer argued against Jewish emancipation in 19th Century Germany. August Bebel denounced left antisemities who thought that a clever way to oppose capitalism was to oppose “Jewish capitalism” first. Bebel called this the “Socialism of Fools”. Jewish Trade Unionists bravely resisted the TUC’s campaign for immigration controls to exclude Jews from Britain in 1905. The Russian Stalinists relied on antisemitism as a staple organising principle of their totalitarian state.

Since the Arab-Israeli war of 1967, left antisemitism has routinely worn the clothes of anti-Zionism. In March 1968 the Polish state organised a purge of Jews from academia by insisting that they signed a statement opposing “Zionism”. Most preferred to leave Poland. Similar antisemitic campaigns were carried out in East Germany just two decades after the fall of the Nazi regime in Berlin.

The 70s and 80s in the UK saw the proliferation of ideas that singled out Israel as being one state in the world worthy of particular vilification. Israel was called an apartheid state, a racist state, a Nazi state. These identities were insisted upon not by reference to Israel’s actions but by reference to Israel’s existence. These false analogies legitimise and license people to treat Jews that think Israel has the right to exist as though they were racist. It allows people who organise against anti-Zionist antisemitism to be de-legitimised as a racist and Zionist conspiracy.

Jim Allen wrote a play in the 80s showing how “the Zionists” collaborated with the Nazis during the Holocaust, as though these two demonic forces faced each other as equals in negotiation in 1940s Europe. And the absurd and offensive idea that “Zionism” and Nazism share an ideological affinity pours fuel on the fire of Israel-hatred.

This period also saw the rise of the “democratic secular state” slogan, which demanded that either Israeli citizens changed their mind about being Israelis or the left would support the Arab conquest of Israel. Jewish Societies in universities were banned because they were held to be racist. And the international UN and NGO conferences on racism in Durban in 2001 were taken over by people that wanted to smash Israel, drowning out any discussion of racism anywhere else.

Since 911, secular Arab nationalism, using the language of socialism, has largely been replaced by currents of political Islam that call for Islamic government throughout the world and whose central critique of Israel is that it occupies “Muslim land”. Some on the left have cosied up to this more openly antisemitic current, employing their shared anti-Zionist rhetoric as a deal-maker. To take antisemitism seriously would endanger these alliances for those on the left that are tempted by them.

One of David Clark’s big errors is to accept the terms of the attack on the left from the right. Some on the right claim that the left is antisemitic. Clarke responds with a defence of the left: “no, the left is not at all antisemitic”.

But reality is more complicated than either of these positions. Firstly, while some on the left negligently allow their hatred of Israel to fuel antisemitism on the left, there are others that oppose them. And Secondly, anti-Zionist antisemitism is not confined to the left, but is also a phenomenon of the centre, of the right,of the Nazi right, of some in the Churches and of political Islam.

Many on the left share this picture too. It is commonly argued by anti-Zionists that to support Israel’s right to exist, or to oppose anti-Zionist antisemitism, defines a person as being on the right. The demonization of Israel is held to be a pre-condition for membership of the left. Indeed, many Jews have the experience of being quizzed on their attitude to “Zionism” before being acceptable in left circles. And it is claimed too that people that are on the left must understand talk of left antisemitism only as a cover by “Zionism” for the crimes of Israel.

All this nonsense needs to be challenged. Democrats and leftists support Palestinian independence and oppose the Israeli occupation of Palestine. Indeed, few people anywhere defend the Israeli occupation. Even within Israel, there is currently a huge (if fuzzy and precarious) electoral consensus for ending the occupation.

As David Clark ought to understand if he has thought about this issue with any care, there is a difference between the criticism of Israeli human rights abuses and the demonization of Israel. There are two coalitions that have an interest in shutting their eyes to this obvious fact.

Firstly, the Israeli ultra-right thinks that it can justify any policy by understanding its opposition as antisemtic.

Secondly, those that do demonize Israel and who want to build a global political movement around the hatred of Israel know that they can deflect any charge of antisemitism by saying that this charge is invented by the oppressors of the Palestinians in order to silence the oppressed.

There is something that should make anyone stop and think twice. Every time you hear a claim that “criticism of Israel is not the same as antisemitism” or that “the cry of antisemitism is used as a cover for the crimes of the Zionists” you should stop and check who is screaming this and why. Very often, this wilful misrepresentation of the problem is employed to cover something. It would be idiotic to argue that criticism of Israel is antisemitic; it would be idiotic to argue that antisemitism is a Zionist invention. Nobody argues it. So why do people feel the need to oppose those that say it? They do so because they want to cloud the debate. They so so because they are afraid to take on the kinds of sharp criticism of anti-Zionism that they would find on Engage if they bothered to look. They say it disingenuously.