Dear Reichsführer,

That's a joke. I hope we can still joke. You remember the gag in Annie Hall when Woody Allen mistakes the question "D'you eat?" for "Jew eat?" I've been there myself. "I hate Jews," I heard a person on a mobile phone saying in a supermarket queue. I asked my wife who was queuing with me what she'd heard. "Highgate, at two," she told me. It's a Jewish joke against ourselves that we find anti-Semitism everywhere. As long as we're joking it means there's nothing to find.

But you're making it hard right now. I am sure you don't mean to. Hating Jews, after all, was something people on the extreme right of politics used to do, and you are on the moderate left. So you can't logically be an anti-Semite, as you continue to tell me. What you are is anti-Zionist, which is different. It bothers me that you think I can't tell the difference. Indeed you insist on it to the point where it is now impossible to disagree with anything you say about Israel without your ascribing such disagreement to Jewish paranoia, as though a disinterested critique of anti-Zionism is philosophically inconceivable to you. This is not a position you can credibly sustain. Only bigots suppose their views are not open to generous dissent. Only racists think all disagreement must be racially motivated. And you are neither a bigot nor a racist.

Your anti-Zionism, however, is tending to an extremism that spills over into something else. You would argue that that is because Zionism itself has turned the screws. And certainly there are cruelties committed in its name. I no more delighted in Gaza than you did. But it is moral hysteria to rewrite the past in order to assuage the conscience of the present. "Anyone who has read the history of Zionism will be aware that its aim was to dispossess the Arabs," a critic of Israel has recently written. To which both the long and the short answer is that anyone who has read the history of Zionism will be aware of no such thing.

For Zionism was never a single movement, and whatever isn't a single movement cannot be said to have a single aim. A complex of ideologies, Utopian, messianic, visionary, practical, communistical, sometimes dreamily idealistic – Jews and Arabs working the land side by side – sometimes just plain desperate, came together (and indeed didn't always do that) to form that which we call Zionism. Far from uniformly expressing Jewish expansionist ambitions, Zionists agreed only on the necessity to escape the grinding fretfulness of an unceasing anti-Semitism and to end the overwrought Jewish self-awareness of which anti-Semitism was the cause. Living with Arabs, not dispossessing them, was to be a way of achieving this.

Since I know you know that, I have a question for you. Regardless of what became of all that idealism, why do you distort its originating impulses? Why must you turn a project for a homeland that moved hearts and stirred imaginations into a cynical smash and grab plot hatched in the far-seeing minds of conniving Jews? I sympathise with Palestinian yearnings because I recognise my own people's in them. Why do you?

Two weeks ago you raised half a cheer for Ahmadinejad's performance at the UN conference on racism. Our man in Geneva, you said, should not have walked out. Ahmadinejad's speech was not, a columnist for this newspaper wrote, "anti-Semitic in the strict sense of the word". Will you allow me to ask how anti-Semitic in the strict sense of the word differs from anti-Semitic in the lax sense of the word? Ahmadinejad, it is true, did not on this occasion employ the word "Jew", only the word "Zionist", but if that was all it took to clear him of anti-Semitism, then by the same logic the BNP has only to remember not to use the word "black" to be innocent of the charge of racism. Keep the world-view, just change the one-syllable words.

A columnist for The Guardian spoke of Ahmadinejad's "toying" with Holocaust denial, as though one can deny the Holocaust a bit, or on alternate weekends. You are not, I know, a Holocaust denier yourself, though you are not beyond "toying" with the Holocaust itself to explain why Israel visits Holocausts on others, a defamation of language, of history, and of the human heart of which I suspect you are secretly ashamed. But that you would lie down with a notorious Holocaust denier simply because he will not lie down with Israel does you no credit. It is possible you don't fully grasp your offence. So in the spirit of our old amity I will explain it to you.

Holocaust denial is the fulfilment of Primo Levi's greatest dread – that those who suffered would never be believed. They were mocked with the promise of disbelief – the assurance that they would never be heeded constituting a further refinement of the tortures the Nazis devised. Holocaust denial is thus continuous with the Holocaust itself; it is the Holocaust still with us. It might claim, in this instance, to be eyeing only Israel, but its essential target is the Jew who lied and goes on lying about what befell him – the "pretext of Jewish suffering", in Ahmadinejad's phrase. "Toy" with Holocaust deniers, make peace with them for no other reason than that they declare war on Israel, and you make common cause with anti-Semitism, however much you insist that anti-Zionism and anti-Semitism are separate entities.

More importantly still, you give succour to fanaticism. Yours is the sleep of reason.

I am not going to say more than I have already said about Caryl Churchill's now infamous play. I do not see myself as its nemesis. Futurity will decide. But it strikes me that there is an indecent haste to go on staging it in some quarters, as though it is seductive by very virtue of the offence it causes. As it happens I am in favour of offence. We must all take it on the chin. But allowing that offended sensibilities determine what isn't shown when those sensibilities happen to be Muslim, you will understand my wondering whether demonstrating disdain for the sensibilities of Jews has become a theatrical end in itself.

A spokesman for Liverpool City Council which is putting money into staging Churchill's play – whatever business it is of Liverpool City Council – states that "for Jews the play may certainly seem anti-Semitic, but not necessarily for non-Jews".

Tell me we are not so far estranged that you cannot hear what's wrong with that.