Crown Prince Mohammed bin Salman is a media-savvy man, and he has just pressed the button he knew would make headlines: Saudi women will be able to drive for the first time in the history of the kingdom. And the act begat the headlines and the headlines begat a tweet from the President of the United States who himself begat a $110bn arms contract with the Saudis three months ago. And so it came to pass. For 24 hours, the world was told about the lifting of the driving ban rather than the chopping-off of heads, the arrest of human rights activists and the horrific war in Yemen.