In the darkness of a winter morning, the world changed. At 3 a.m. on Sunday in Geneva, my iPhone – and that of countless other journalists awaiting the outcome of the Iran nuclear talks – exploded with tweets announcing that an agreement had been reached. After hours of slumber, we found ourselves watching live pictures of seven relieved and exhausted foreign ministers engaged in what might be termed a group hug. The fact that the huddle’s participants included John Kerry, the US Secretary of State, and Mohammad Javad Zarif, the Iranian Foreign Minister, showed just how remarkable a moment this was.After the photo-opportunities and the mutual congratulation, Messrs Zarif and Kerry addressed back-to- back press conferences between 4.30 and 5.30 a.m. Each of them sold the