Of Iran. He's running in June's elections. I'd have to imagine that the prospects for big agreements that prevent nuclear proliferation in the region get a lot better with him running Iran while Obama is our president. Of course, the bulk of the power (including the power to actually use nuclear weapons, if Iran should acquire them) sits in the hands of the mullahs and not the president. But a Khatami administration with strong popular support would probably be able to get things done. Even dictators have to worry about popular sentiment at some level.
According to the article, "Unofficial polling shows Khatami would beat the incumbent by a two-to-one margin." Which is great, and I have to imagine that Ahmadinejad's anti-American rhetoric loses a lot of its appeal when Barack Obama is president.