THE president of Iran is a powerful communicator. When Mahmoud Ahmadinejad spoke live to the nation last month, he managed to combine seductive reasoning, patriotic appeals and more than a hint of menace. For once, though, he left even his most fervent supporters unmoved, for he was announcing the beginning of the end of subsidies on which millions of them depend. These measures are the gamble of his presidency—and may be the most important economic reform in the Islamic Republic’s three-decade history.