So there we have it. In the end, Penny Mordaunt couldn’t quite scrape together enough nominees to make it over the threshold and trigger a full leadership election. Perhaps if Boris Johnson had pulled out a day or two earlier, she might have been able to build the requisite momentum. But it wasn’t to be. Now Rishi Sunak will be the UK’s latest prime minister. His mission, which I suppose he now has no option but to accept, is somehow to keep the Conservatives united enough to govern and thus avoid what would be a catastrophic general election. It will be no easy task. While the Tories have a solid majority on paper, the parliamentary party is now so fractious that any one of a number of increasingly well-organised caucuses could hold government business to ransom. Sunak’s first challenge is going to be finalising the medium-term fiscal statement, which is currently being prepared by Jeremy Hunt. That means drawing up a programme of spending cuts and tax rises worth tens of billions, and then persuading restive backbenchers, elected on a spendthrift manifesto in 2019, to pass it. Will he be able to? He might have secured a commanding nominations lead among MPs, but that should not be taken as evidence of any deep well of enthusiasm for a Sunak programme, rather than simple relief that he is neither Johnson nor Liz Truss. At that point, the awful state of the polls may end up being the new prime minister’s best friend. He and Hunt, or whomever he chooses to serve as his chancellor, can threaten unhappy MPs with a general election if vital government business is blocked. (Since the repeal of the Fixed-term Parliaments Act, MPs can no longer prevent a prime minister going to the country.) Beyond that, it isn’t yet clear what the next two years of a Sunak government will look like. Economic circumstances have changed dramatically since his last leadership campaign a couple of months ago, and we don’t yet know which of his various pledges are going to fall by the wayside. Readers who take the time to read up on his campaign promises, however, may be surprised by the candidate that emerges. Because one of the strange things about Sunak is that he’s been painted as the liberal, establishment candidate, even though he is much more conventionally rightwing than either Johnson or Truss. We see that he’s committed to somehow delivering the Rwanda policy; a hard cap on the number of refugees accepted into the country; and a bid to double the number of overseas offenders deported annually. There will also be a Brexit delivery unit, aimed at reforming or scrapping retained EU law by the next election. Given all that, it’s perhaps surprising that rightwing MPs were reportedly trying to find a Plan B candidate in case Johnson, of all people, didn’t run. Yet at the moment, such is the muddled nature of Tory politics that they rallied first to Truss, a remainer, and then Johnson, a flip-flopping leaver, rather than the candidate who backed leave from the off. There will also likely be clashes on Northern Ireland – the government’s NI protocol bill is set for a savaging in the House of Lords, and the European Research Group is watching for any sign that ministers may back down on giving a role to the European court of justice – and over levelling up, where Sunak will struggle to find the cash to meet his commitments to Ben Houchen, the mayor of Tees Valley, and the Northern Research Group of MPs. Our new prime minister was, at one point, one of the most popular politicians in the country. But this was because extraordinary circumstances demanded that he throw money at the electorate without asking them to pay for it. There will be no repeat of that this time. Can Sunak come through as the acceptable, modern, metropolitan face of austerity? We’re about to find out. Judging by his impressive performances on the stump during the last contest, it might just be possible. By his starey, strangely robotic acceptance speech of this afternoon, not so much. Henry Hill is the deputy editor of ConservativeHome