Not only should the Iranian President not be prosecuted (by Germany!) for expressing views (in Iran!) that many find offensive, neither should anyone else. For several reasons, statutes criminalizing "denying the Holocaust" tend to discredit the legal systems that contain them:

(1) One group’s feelings may be protected, while another group of offended are treated to a lecture on the sanctity of free speech (e.g., those notorious Dutch cartoons).

(2) The laws do not define the event whose occurrence is allegedly being denied. They therefore blur the difference between universal and particular skepticism. In practice, Holocaust denial laws treat those who raise questions about particular events as lunatic doubters of a whole class of events. "The Holocaust" refers to many thousands of events over a dozen years. Some historical narratives that were once widely accepted as having a factual basis have lost that status. Only historical inquiry, not legal compulsion, can responsibly impute credibility to one account and deny it to another.

(3) The irony of punishing speech in the name of preventing a “resurgence of Nazism” may be lost on the punishers, but not on their victims and their supporters. Those laws therefore become unintended liabilities in the fight against any such “resurgence.”