The principles of freedom of thought, freedom of speech and a free market of ideas seem to require that Columbia remain neutral with regard to any political positions it could adopt. However, in order to retain integrity in its standards, Columbia cannot acquiesce to debate some issue simply because it is controversial; there must be some potential insight into new ideas and perspectives (essentially, some education) gained from engaging in the debate. Otherwise, Columbia risks legitimizing an argument that does not even reach the threshold of a coherent argument.
Mahmoud Ahmadinejad is a polarizing figure, not only because of his nuclear ambitions for Iran, but because of baseless, inflammatory comments he has made towards Israel in the past. Ahmadinejad has denied the Holocaust, and has said something to the effect of "the regime occupying Jerusalem should be wiped off the map." These statements cannot be considered a legitimate point of view on an unsettled historical question or a legitimate policy of genocide. Nonetheless, Ahmadinejad has been routinely ignored and outright derided by world leaders who reasonably want to undermine his power, which has the tendency to create a powerful backlash in the populations that are similarly disenfranchised by global powers. This repression sadly amounts to a failure of global leaders to reinforce the principles of freedom of speech and a free market of ideas, which were once the allure of the American way of life. Instead of allowing Ahmadinejad's claims to fail due to their incoherence, his ideas are blocked from discussion and therefore strengthen his position in the eyes of his already-polarized population.
That being said, Columbia invited Ahmadinejad to speak on the condition that he answer questions directly challenging those statements, hypothetically aimed at exposing the untenability of these positions. By actually engaging him and then disarming his arguments, we are far more likely to de-legitimate his position than by ignoring his claims and letting his rhetoric fester in a population without anyone to contradict his claims. Columbia does risk actually enhancing his reputation if people assume that his invitation implies that his ideas are worth "debating." Because of the respect being accorded to this odious character, people fail to draw the reasonable inference that Columbia has invited him here specifically to challenge him. As far as I am concerned, the University has enhanced its reputation for academic independence (which may incidentally exacerbate its "ivory tower" reputation amongst those who find that a bad thing) and somewhat sober intellectual discourse by inviting Ahmadinejad to challenge him.
As far as the student body is concerned, there is another point of pride, with some serious exceptions. The vast majority of the student body is taking this momentous event rather seriously and are engaging in civil, respectful demonstrations and dialog with their opponents. I am very happy that many people are protesting Ahmadinejad personally, as well as his policies, but I am somewhat dismayed with people who are angered at the administration for inviting him to speak. I understand that this may be motivated by a fear for legitimizing Ahmadinejad's positions (and this may be the case--we have yet to see), and that one might not want to give Ahmadinejad one more quantum of publicity than he already has.
However, some much more disastrous arguments have also been advanced. Some have argued that Ahmadenijad is not entitled to enjoy a right of free speech because he is not American (tell that to every legal or temporary resident who is in America temporarily), or because his policies have resulted in executions that kill innocent civilians or violate due process (by that logic, any President--especially Bush--should be protested with the same vehemence). These arguments smack of fascism; the idea that one can selectively allow only certain arguments to be traded in the marketplace of ideas are even more steps toward a slippery slope to a totalitarian society. It is my fervent opinion that ideas must be defeated on their own terms, or else the backlash effect will only motivate those who are disenfranchised by the current state of world affairs to take up arms for "their side."
We will see how the event plays out. I'm sitting on the lawn in front of the screen right now, and will live-blog any momentous developments if they come up.