It was not the stuff of ordinary political debate. Inside Columbia University in New York yesterday, Iran's President, Mahmoud Ahmadinejad, was attacked as a "petty and cruel dictator". Outside, furious protesters competed with the sound of helicopters to voice their anger that the Iranian leader was being allowed to speak at all.
The man who invited him, the Columbia University president, Lee Bollinger, began by railing at his guest's record of Holocaust denial. "This makes you quite simply ridiculous. Mr President, you are exhibiting all the signs of a petty and cruel dictator," he said. When he was finally given the floor, a calm and smiling Mr Ahmadinejad defended himself and called his critics misinformed.
"There were many insults in this and there were many incorrect statements regretfully," he said.
Protesters had started to gather outside the university gates on Sunday to voice their anger at its decision to hold the forum, which threatened to eclipse events several miles away at the annual General Assembly of the United Nations, where Mr Ahmadinejad is scheduled to speak today.
Some demonstrators held up banners showing the front page of a local newspaper telling the President to "Go to Hell" with his image sliced though by a diagonal red line.
Cecille Low, a Holocaust survivor, denounced the decision to host Mr Ahmadinejad as "an insult" to her and other victims of the Nazis: "If he wants to speak he can speak on any street corner."
An Iranian-born student who identified herself as Mary took a different view: "I feel he should have the right to speak. Demonising him is not going to change anything in the world."
Mr Bollinger defended his decision not to cancel the forum. "It's extremely important to know who the leaders are of countries who are your adversaries, to watch them, to see how they think, to see how they reason or don't reason," he said.
Neil Shachter, a professor of medicine at the university, was among the protesters. "It is hard to say who is the greater moral monster, the President of Iran or the dean of the university who has said he would have invited Hitler before the Second World War," he said.
Protesters also gathered outside the UN headquarters organised by an alliance of Jewish groups. In an unusual gesture, their ranks were joined by the Israeli Foreign Minister, Tzipi Livni. The Iranian President has been quoted in the past saying he would like to see Israel "wiped off the map".
Mr Ahmadinejad has voiced his amazement over the furore last week when he sought permission to lay a wreath at Ground Zero to the victims of the attacks of 11 September 2001.
In a sometimes testy question-and-answer session, Mr Ahmadinejad told the moderator: "You ask the questions but you ant the answers the way you want to hear them. This is not a free flow of information. In Iran when you invite a guest, you respect them, that is our tradition."
The President refused to address questions regarding the persecution of homosexuals in Iran. "In Iran we do not have homosexuals like you do in your country. In Iran we don't have that phenomenon," he said, to ripples of laughter in the audience.
On his alleged claim that the Holocaust was "a legend", he said: "I am not saying it didn't happen." However the President said that there should be "more research from different perspectives" on the history of the Holocaust.Reuse content