Two remarkable essays by Berneri come to mind — a 1934 essay entitled "Against the Racist Delirium" and a 1935 booklet entitled "The anti-Semitic Jew". Both works are sketchy — they were written in exile, without the benefit of a proper library to consult. Thus they read more like drafts of a more substantial project, especially the latter, which delves into the question of why some Jews turn against their own people, helping in the process to foment anti-Semitism. But the essays are insightful — and morally uncompromising. At a time when Nazi anti-Semitism was being met across Europe with only mild disapproval at best, Berneri described it for what it was — a vile and violent delirium. As for the Jewish turncoats whom he studied in his 1935 essay, suffice to mention Berneri's opening remark: "The death of an anti-Semite is one of those things that uplifts my heart."

At the time, anti-Semitism, so central to Nazi ideology, was summarily dismissed, played down, or at most considered a mere embarrassment —as long as it threatened Jews alone. Although Berneri  was by no means alone in sounding the alarm against Nazi anti-Semitism early on, he was swimming against the current and pointing an accusing finger at that very aspect of Nazism that people found least distasteful because of their own prejudices. His words  thus fell on deaf ears. But they were prescient nonetheless.

Eventually, he was proved right. Stopping Nazism early on would have spared Europe tens of millions of victims and widespread destruction. Rushing to the rescue of Spain's beleaguered Republican government in 1936, nipping fascist aggression in the bud, might have yielded different results. For example, it might have tamed Hitler's expansionism. But Hitler's brutality in Spain only fuelled the appetite for appeasement in Europe, and when he demanded the Sudetenland for Germany, the two great Western powers of the day — France and Great Britain — sold the young and fragile republic of Czechoslovakia down the river. Not invited to the Munich conference that sealed their fate, the Czechoslovaks were told that, were they to reject the deal, they would be left to fend off Nazi Germany by themselves.

As Western powers sit with Russia and China in Geneva to negotiate with Iran, is it so hard to see history repeating itself?

I was thinking all this as Rouhani stood at the UN podium in New York and in the days that followed, until Israel's prime minister, Benjamin Netanyahu, spoke from the same platform.