The Columbia dean who recently said he would have invited Hitler to speak at the university, and who has invited Iran’s president, Mahmoud Ahmadinejad, to speak there this afternoon, said in an interview yesterday that providing a forum for the most dangerous international leaders to answer questions from Columbia students and faculty could help shape world events.

The acting dean of Columbia’s School of International and Public Affairs, John Coatsworth, told The New York Sun that if the Nazi leader had agreed to speak and answer questions at Columbia University in 1939, the event could have helped changed Hitler’s views of America and this country’s understanding of the intentions of the Hitler’s regime.

“Democracy really does work,” Mr. Coatsworth told the Sun. “Hitler would have never come to the U.S. because he considered that it was a weak country with no capacity to beat him, but had he come to the United States in 1939, he would have found a country with lots of admirers of his regime. An appearance by Hitler at Columbia could have led him to appreciate what a great power the U.S. had already become.” If Hitler had visited Columbia, President Roosevelt may have been able to convince Congress to get involved in the war earlier, the dean said.

Mr. Coatsworth said Columbia would not have extended an invitation to Hitler in 1945, after he was branded a war criminal.

Mr. Coatsworth caused an uproar over the weekend when he said in an interview with Fox News that Hitler would have been welcome at Columbia University if he had agreed to field questions from faculty and students.

By yesterday evening, the video of Mr. Coatsworth’s appearance had been viewed on YouTube 184,851 times. Mr. Coatsworth said he had received a flood of emails criticizing his comments, and planned to respond personally to each one.

Mr. Coatsworth also defended Columbia’s decision to host the Libyan strongman, Muammar Gadhafi, via satellite in 2006. “Within months after Gadhafi’s appearance at Columbia his policies changed, and not long after, he decided to abandon his desire to acquire nuclear weapons,” Mr. Coatsworth said.

In 1933, the president of Columbia, Nicholas Butler, drew similar fire for extending an invitation to a Nazi envoy, Hans Luther, to deliver a lecture. “Inviting the Nazi envoy to lecture on the foreign policy of his government and giving him an official reception means not only failing in our duty to oppose the Nazi onslaught on culture and in our duty to defend our German colleague but signifies, if not open endorsement of the Nazi actions, at least placing their principles on the same level with other viewpoints,” a campus group, the Columbia Social Problems Club, wrote in a letter to Butler that was published in the New York Times in November 1933.

Mr. Coatsworth has been defending Mr. Ahmadinejad’s visit to the campus as an opportunity for students to question and learn from opposing points of view. Butler used a similar argument in 1933 to defend Luther’s appearance on campus. “Columbia University has been for more than a century and three-quarters a home and centre of academic freedom,” he wrote in response to the student group. “There is no subject which a company of scholars such as that assembled on Morningside Heights, is not prepared to have presented to it by a man or woman of high intelligence and good manners, and to hear fully discussed and debated.”

Mr. Coatsworth, a former professor of history at Harvard University and the author of seven books on international history, said yesterday that the university’s Center for Jewish Studies helped balance of the viewpoints of speakers invited to campus by inviting scholars and survivors of the Holocaust to campus.

The Iranian leader is appearing at Columbia as a part of its World Leaders Forum. The president of Malawi, Bingu wa Mutharika; the president of Turkmenistan, Gurbanguly Berdymukhammedov, and the president of Chile, Michelle Bachelet Jeria, are also scheduled to appear today at the university.