It's not only that Iran refuses to recognize Israel.
The Islamic Republic's official representatives are generally barred from speaking with Israeli diplomats or even uttering the word Israel, preferring to describe their regional enemy as "that Zionist entity."
But sometimes you just really need a place to sit.
Iran's permanent representative to the International Atomic Energy Agency, Dr. Ali Asghar Soltanieh, is pictured here at an IAEA meeting last month, seated at the Israeli delegation's desk while conducting his official business.
Soltanieh is engaged in a discussion with a member of the delegation of Ireland, which presides over the IAEA's nuclear safeguards committee, and a Cuban diplomat. He is accompanied by two other Iranian officials, according to a source who furnished Turtle Bay with this photograph.
It's hard to imagine how the top Iranian diplomat, after serving more than six years as Tehran's envoy to the atomic agency, wound up in the Israeli seat without an alarm bell going off in his head. You'd think there was a protocol office within the Iranian foreign mission responsible for avoiding such a diplomatic faux pas.
If not, maybe there will be from now on.
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Longtime Washington Post correspondent Colum Lynch reports on all things United Nations for Turtle Bay.