Billionaire philanthropist Ronald Lauder, president of the World Jewish Congress, said he will be encouraging donors to cease contributions to Columbia University “until such a time as antisemitic despots are no longer welcome on your campus.”

In a letter to Columbia University President Lee Bollinger, Lauder said the last straw for him was the university’s invitation to Malaysian Prime Minister Mahathir Mohamed, who is slated to speak on campus on Wednesday. Mohamed is known for his extremist views and for repeatedly espousing antisemitism, including smearing Jews as “hook-nosed” and claiming “Jews rule the world by proxy.”

Amid calls from opponents of antisemitism to nix the visit, Bollinger defended the invitation, writing in a letter to student groups that “this form of open engagement can sometimes be difficult, even painful.”

“But to abandon this activity would be to limit severely our capacity to understand and confront the world as it is, which is a central and utterly serious mission for any academic institution,” Bollinger argued.

In his letter to Bollinger, Lauder retorted, “I understand, from your statement, that you believe it is in the interest of education that all views are aired at Columbia. With all the world leaders and statesmen in New York this week, I wonder why this man’s views are so vital?”

The Jewish leader called on donors to withhold future contributions:

I am not a Columbia alum. I went to Penn and my family and I have been among its largest benefactors. I will honestly tell you that if Amy Gutmann at Penn were as consistent in allowing antisemitic speakers on her campus as you are at Columbia, I would seriously consider stopping my funding. Accordingly, I will be encouraging all of my friends to immediately cease any of their contributions to your institution until such a time as antisemitic despots are no longer welcome on your campus.

Columbia and Bollinger faced widespread criticism in September 2007 for playing host to then-Iranian President Mahmoud Ahmadinejad, infamous for denying the Holocaust, rejecting Israel’s right to exist and calling for the Jewish state’s destruction. Iran is a leading state sponsor of worldwide terrorism.

Lauder noted Ahmadinejad’s speech as well as instances of pro-Israel students reportedly facing an atmosphere of intimidation.

The World Jewish Congress leader wrote:

I have watched, with growing concern, the incidents and incitement directed against Israel on the Columbia campus, that are nominally called political activity, which have made many Jewish students on your campus less than comfortable. Jewish organizations, including the World Jewish Congress, have been understandably upset with this ongoing situation at Columbia, because the complaints from students have grown, along with the increased vitriol against them. So with that as the backdrop, along with the 2007 speech by a hate filled, Holocaust-denying Iranian president, Mahmoud Ahmadinejad, I am joining the growing chorus of those upset over your giving Mohamed an opportunity to air his anti-Semitism on your campus.

In his response to critics, Bollinger wrote that Mohamed’s invitation should not be taken as “validation” or an “endorsement” of the politician’s views.

“I find the anti-semitic statements of Prime Minister Mahathir to be abhorrently contrary to what we stand for, and deserving condemnation. Nevertheless, it is in these times that we are most strongly resolved to insist that our campus remain an open forum and to protect the freedoms essential to our university community,” Bollinger wrote.