Among those persons, events and subjects in our culture that occupy the fenced-off area marked "Handle With Care", one particular topic is additionally locked in a lead safe, wrapped in barbed wire, electrified and surrounded by a moat full of sharks: the Shoah. As the Second World War drew to a close, it became apparent to all that in Nazi-occupied Europe, shrouded by the "night and fog" of war, a special kind of evil had been wrought; no makeshift massacre in the heat of battle, but a meticulously planned and industrialized slaughter, ordered by educated men and executed by every arm of state and society. Humanity had a new definition of evil.

But of course, there's no such thing as a subject entirely off-limits to comedy. In fact, the more taboo the subject, the more irresistible the fascination - what Poe called the "imp of the perverse". This is the voice at the back of every mind that wants to laugh out loud at funerals and scream "WHAT THE HELL IS THAT?!?" when presented with baby photos. It would be surprising if a body of humor hadn't developed around Nazism, Hitler and the Holocaust, doubly so because the people most directly affected - the Jews - take such pride in their comedy. To resist it would be contrary to human nature.

This is a fact that sadly seems to have escaped the Anti-Defamation League, America's leading voice against antisemitism, which last month took legendary comedian Joan Rivers to task for making the following joke (in reference to Heidi Klum's Oscar night dress):

The last time a German looked this hot was when they were pushing Jews into the ovens.

In the ADL's defense, it is their job to be humorless, to a large extent. For nearly a century (they turn 100 in October), the group has done a sterling job of fighting bigotry in all forms, which sometimes demands an inflexible approach. In addition, this being Joan Rivers, the joke is undoubtedly tasteless and provocative in the extreme. But does that mean the rebuke was deserved?

I would argue not. Like pornography or art, bigotry is something you know when you see, and I don't see it here. This isn't a libertarian, anything-goes defense, however; it's just as intuitively clear to me, as it should be to every reader, that some jokes about the Holocaust really are unacceptable in decent society. One example, which I recount only for purposes of illustration, was current when I was a schoolboy:

How many Jews can you fit in a Volkswagen?

Ten thousand; two in the front, two in the back, the rest in the ashtray.

Again on the level of pure intuition, that punchline hits me like a kick in the gut. Here is real, unmistakable nastiness of a fetid, furtive kind, whispered in corners after a cautious glance over the shoulder. I feel dirty even typing it out. But this raises the question: why do we feel this way? Why does Rivers' joke have the sting of deliberate shock without any of the other joke's malice? What separates acceptable from unacceptable?

Here's one very obvious observation to start with: Joan Rivers is Jewish. This doesn't give her (or any other Jewish person) a free pass when it comes to Jew-baiting - Jews make the best antisemites, just look up "Gilad Atzmon" - but it does alter the context, draw a little oxygen from the flames. This is liable to infuriate the kind of tedious reactionary who likes to complain about not being "allowed" to use the N-word (why would you want to?), but it's a generally acknowledged principle, just as we all feel free to kvetch about our own family but feel immediately defensive when strangers do it. The same goes for the audience. Rivers is addressing a wised-up crowd of Hollywood obsessives who are disproportionately likely to be Jewish or know Jewish people; at the very least, it's not hostile to Jews (very possibly hostile to Israel, but that's another question entirely).

Now consider the second joke. I grew up in Cardiff, Wales, where the Jewish community, as in most British cities is relatively healthy but extremely small. Small enough, in fact, that it could generally be assumed that the audience for a playground joke would be all-Gentile, as would the person telling it. Even when this happened not to be true, that was the context. It will be seen that this lends the joke an entirely different color, even before we get to the substance of the words. This was about a secure, dominant majority group having fun at the expense of a tiny, barely-visible minority. Just as an imbalance of power can turn innocent horseplay into bullying, this dynamic turned a joke (though a far-from-innocent one, as we'll soon see) into an exercise in exclusion.

This is only to look at the packaging. The meaningful difference between Rivers' joke and my classmates' is in their content, and the way that content interacts with the context described above. The key question is: who or what is being mocked?

In Rivers' joke, the answer is quite clearly "the Nazis". The remark gains its shock value by introducing the modern, clean, reassuringly boring Germany in the form of Heidi Klum, then forcing us to associate that with the other side of German identity, the legacy of Nazism. This is deliberately done in the most brutal, graphic way possible - "pushing Jews into the oven" - with a note of pitch-black irony - the poor German just getting "hot" while the Jew actually burns to death. The point here is less at the expense of modern Germans - who have probably done a better job of remembering the Shoah than Americans have with slavery - than the emollient, reassuring postwar consensus that drew a heavy black line between the past and present and marked the former "a long time ago".

This was arguably necessary for the sake of diplomacy and a quiet life, but in truth, it wasn't that long ago, not historically speaking. By suddenly and unexpectedly forcing the Holocaust into the forefront of our mind, if only for a few moments, Rivers is actually being quite subversive, in an offbeat way. This is only reinforced by the context: the smug, self-congratulatory and, above all, safe bubble of unreality known as the Academy Awards. Rivers' schtick* has long been to play against that bubble with her scorchingly rude fashion putdowns, but this took it to another level. In other words, the joke can be considered of a piece with other attempts to keep the Shoah alive in popular memory. Joan Rivers: one-woman Yad Vashem? Not quite, but she is one of the good guys.

That can't be said for whoever first devised the other joke. Here, the object of mockery is just as clear: Jews. Not just Jews, in fact, but dead ones, the more so the better.

In a formal sense, the joke relies on the same shock of recognition that powers the other, forcing us to think about genocide. Where Rivers wants to make us picture a monstrous crime - that graphic "pushing Jews into the oven" - here the Holocaust is invoked merely as an instrument for the delivery of a cheap punchline. It's not even wholly clear what the "joke" is supposed to be, apart from shock value, but what it isn't is any kind of attempt to make us think of the Shoah as a real event with real victims. When combined with the social context elaborated on above, it becomes truly toxic, almost gloating - "we can joke about this, it never happened to us, it happened to the people who aren't in the room".**

I have heard some express the opinion, quite understandably, that comedy should leave some subjects alone, that the associations involved are simply too painful. I have a lot of respect for people who feel this way, but as I said at the beginning, the demand may be impossible: there is nothing more human than pressing the big, red button. When it comes to Holocaust humor, the rule to avoid giving offense turns out to be the same as for all other comedy: be on the side of the weak against the strong, the oppressed against the oppressors and the difficult against the path of least resistance. In other words, act like a human being to avoid being mistaken for anything less.

That's a heavy note to leave a humor column on, so I'll leave you with a third Shoah-related joke, this one firmly in the Rivers category and somehow quintessentially Jewish, at least to this Gentile. It's an old one with a million variations; this one is recounted at the start of a classic essay by Christopher Hitchens:

Two old Jewish men are sitting on a park bench in Berlin in the early 1930s. Things are not yet so bad, but that doesn’t mean they won’t get worse. One of the two is solemn­ly reading a Jewish newspaper. The other is scanning a Nazi paper, and laughing out loud. Finally, the first man stops reading and says, “It’s bad enough that you read that pro-Hitler rag. But to laugh at it!”

The second responds with a shrug. “What if I read your paper? It tells me about Jewish windows being broken, Jewish shops boycotted, Jewish children beaten up in school. So ... if I read the Hitler paper it tells me that we Jews control the whole world.”

* I'm not deliberately using more Yiddish words than usual, it just seems to be happening. Oy.

** Some of you may find it a little too convenient that I can't remember who first told me this joke, and that I was apparently immune to its appeal. In all honesty: I can't remember, and even if I could, we were small children (younger than ten) and I'm certain that whoever it was would now be deeply ashamed. Memory being what it is, I don't think I ever recounted it, but I easily might have done. I certainly never confronted anyone, much to my later chagrin. The playground, especially among little boys, is a place of cowardice and conformity.