In a bitterly worded letter, the Israeli ambassador to the United States on Friday accused the Council on Foreign Relations of making a “terrible mistake” by inviting President Mahmoud Ahmadinejad of Iran to a meeting with the group earlier this week.

“Some of those upset with the council’s decision have compared it to hypothetically inviting Hitler to a meeting in the 1930’s,” the ambassador, Daniel Ayalon, wrote to the council’s president, Richard N. Haass. “In fact, meeting with Ahmadinejad is worse: Hitler did not openly call for genocide in the 1930’s, and today we have the lessons of the 1930’s to guide us. Foremost among those lessons is that appeasing fanatics like Hitler and granting them legitimacy leads to genocide and war.”