There is a chance that all this will prove unduly pessimistic. Some officials advance a slender case for optimism about Mr Ahmadinejad. He is, at least, a known quantity. As a visceral hardliner with nothing to prove, he may be better placed to make a deal on the principle that only Richard Nixon, the staunch anti-communist, could have restored America's relations with China. Moreover, Mr Ahmadinejad clearly enjoys the trust of Ayatollah Khamenei – and no rapprochement with the West could happen without the Supreme Leader's approval.