This is probably the best argument for allowing Ahmadenijad to speak at Columbia today:
A rally where each speaker denounces Ahmadinejad's reactionary policies and just a few call explicitly for military action will still be perceived, on campus and around the U.S., as pro-war. The right-wing media, from Fox News to the New York tabloids, has already jumped on the event, and will spin it to favor their cause. Conservative organizations with no affiliation to Columbia's campus, such as the David Project, have already signed on to the rally on Facebook, and are likely to distribute hundreds of warmongering flyers and picket signs. The rally will seem to be a sea of pro-war demonstrators -- and the more people who attend it and the more organizations that endorse it, the more powerful this disastrous message will be.
A U.S. attack on Iran, which is not an inevitability but is a real possibility, would have consequences just as terrible as the invasion of Iraq. Thousands would die in initial air strikes, and more in the resulting backlash and regional conflagration. The work of Iranian campaigners for free speech, women's rights, and lesbian and gay liberation, and against racism and anti-semitism, would be set back immeasurably. As Iranian Nobel Laureate Shirin Ebadi has pointed out, "Human rights are not established by throwing cluster bombs on people. You cannot introduce democracy to a country by using tanks."