David Cameron's closest colleagues say that he's a lucky politician. When it comes to the biggest gamble of his career, his luck has dramatically run out.
In a snub to him, a snub to the status quo, and a snub to the entire political establishment, the UK has voted to leave the European Union, to tear up the settlement the country's had for decades, unleashing, perhaps, huge opportunity, or perhaps huge risk - perhaps both.
All the traditional political rules have been broken - that voters tend to vote for what the consensus tells them is in their economic self interest. And that referendums, those votes where there is only black and white, no shades of grey, tend to produce the status quo. And it could now shatter the prime minister's career.
Despite public protestations to the contrary, letters from loyalists, promises of support, the prime minister's time in office may well be curtailed. The tension - can he stay in office with his authority drained by a defeat, or will he endeavour to stay in order to provide stability at a time of tumultuous change?