IT WAS sweeping, ruthless and decisive. “Brutal reshuffle, prime minister?” shouted reporters as Theresa May arrived back in Downing Street after a morning going through Cameroons like a hot knife through butter. A smile dashed across the new prime minister’s face as she strode into her new house. What to make of it? Overall Mrs May has tilted the government to the right. But the picture is also more complicated. It helps to divide her appointments into two sorts: those related to Brexit and those not. Into every role that has lots to do with Britain’s exit negotiations, she has slotted someone who campaigned to make that happen. Boris Johnson is foreign secretary, Liam Fox international trade secretary (a new cabinet-level role), David Davis the minister for Brexit (ditto) and Andrea Leadsom secretary of state for the environment, food and rural affairs (a role that will involve dealing lots with farmers who stand to lose European subsidies). The thinking, it seems, is that putting Brexiteers in these posts will make up for Mrs May’s own anti-Brexit stance before the referendum and help her to sell the inevitable concessions that Britain will have to reach to a public whose expectations of any deal seem far to outstrip the likely reality. Meanwhile she has appointed moderates and reformers to some of the key public service posts. Amber Rudd, an impressive Remainer—and more of an instinctive liberal than the new PM—goes to the home office. Britain’s new education and equalities secretary, Justine Greening, is state-educated and in a same-sex relationship. Damian Green, a One Nation stalwart, is the new welfare secretary. Perhaps most promisingly Greg Clark, an Osbornista and the brains behind the recent revolution in cities policy, takes the helm of a new industry and energy department. Reassuring, too, are the names not favoured among the domestic appointments: Theresa Villiers is out, Iain Duncan Smith seems to have been passed over and Chris Grayling, the right-wing Eurosceptic who ran Mrs May’s campaign (her “bit of rough” for the grass roots, as it were) will be disappointed with the transport brief.

What do these appointments tell us? The new prime minister seems determined to break with the Cameron years. Her assessment of her predecessor—discernible, between the lines, in some of her statements and actions as home secretary—is now crystal clear: Mr Cameron’s government was too posh, too cocky, too blithe about globalisation’s merits, too metropolitan. Too Notting Hill. It failed to connect with the cultural and economic insecurities of ordinary voters. She plans to tack in a more Eurosceptic and more economically interventionist direction. As I write in my column this week: “[Theresa May] is not anti-globalisation… But she does want to take the edges off it, get it under control and make it neat and manageable.” Her strategy now: to insulate herself from the politics of Brexit with a ring of steel (in the form of Mr Johnson, Mr Davis, Mr Fox and Mrs Leadsom) and get on with domestic reforms.

I’m not convinced this is the way to go. Brexit will be the defining issue of Mrs May’s premiership. It cannot just be cordoned off. Moreover, its success depends not just on how it is perceived at home, and how it goes down in the Conservative Party, but what it actually achieves. On that front, the prime minister has appointed the wrong people. Installing Mr Davis may buy her a fleeting moment of respite from the suspicious accusations of, say, John Redwood, but it does not contribute to the formation of a capable negotiating team.

It is true, the MP for Haltemprice and Howden was a Europe minister in the 1990s. But he was not exactly well-suited to the job: progress in Brussels, as even Margaret Thatcher showed, is achieved by nimble deal-making, the art of persuasion and sensitivity to the political constraints on other leaders. Mr Davis demonstrated none of these. Stephen Wall, Britain’s permanent representative to the EU at the time, recalls: “Every week, before each negotiating session, I would receive pages of minute instructions from the Foreign Office, personally authorised by David Davis. The Foreign Office could have saved themselves a lot of trouble by sending a one-line instruction: ‘Just say no.’ There was virtually nothing on the agenda that was palatable to the government.”

In all likelihood Mr Davis will be just as unconstructive this time: his strategy for Brexit, published just two days ago, is wildly optimistic and suggests that he is totally unprepared for the rigours of the negotiation ahead. I would not be remotely surprised if this particular thread of our story ended with him flouncing out, talks at a deadlock, and blaming Mrs May for failing sufficiently to underwrite his fantasies.

And then there is Boris Johnson. He is a liberal at heart and probably never thought Brexit a good idea. Yet his appointment is the most troubling of all. For it suggests that the prime minister sees Brexit fundamentally as a presentational task: about appearances, about selling the deal to the audience at home.

These things matter, of course. But they melt into insignificance compared with the geological scale of the mountain the country must now climb. In its continent, Britain must now rewrite its relationship with its largest trading partners, extricate itself from four decades of treaties, laws and conventions and negotiate painful trade offs. Farther afield, it must reconfigure its role in the world and its relations with other countries. This is not some hermit state, but one of the most globalised and internationally interdependent economies on the planet. It rises and falls on its relations with the outside. And in the Foreign Office, it has a Rolls Royce of a foreign ministry; storied, wise and staffed with some of the cleverest people in Europe. Properly used, that department and its network of embassies is the motor that gets Britain from where it is now to somewhere vaguely resembling where it wants to be in a couple of decades’ time.

It should thus be led by someone capable of working the machinery. But in Boris Johnson it is not. The new foreign secretary is clever, worldly and magnetic, as I argued in my recent profile of him. Personally he is likeable. But he is also gaffe-prone and the progenitor of a series of undiplomatic comments about other peoples. Much more damning: he is unscrupulous, unserious and poorly organised. His leadership campaign failed not because he lacked the potential to go all the way, but because he struggled with basic daily tasks. Michael Gove only plunged the dagger twixt the former mayor’s shoulder blades because he had been driven to exasperation by Mr Johnson’s forgetfulness and lack of preparation (rumour has it he had written barely a third of his announcement speech by the early hours of the day he was due to give it).

On one level, it is easy to sympathise with Mrs May’s decision. Mr Johnson is weak and manageable. Packing him off to parts foreign will keep him out of the way and limit his ability to plot a new path to 10 Downing Street. He will put a Brexiteer face on a government led by a Remainer. Yet all this betrays an odd complacency about the drama into which Britain has now thrust itself. Brexit, believe it or not, is about more than opinion polls and Tory traumas. It is about Britain’s future: a future that will turn not on the doubtful willingness of foreign governments to bend over backwards to tolerate British demands, but on the ability of the government in London to persuade them of its case and reconcile the desires of the British electorate with those of EU27 electorates. Brexiteers do not like to admit it, but whether or not Britain gets a deal that will satisfy its population and rein in the populist surge in the country is largely a function of that ability.

However much Mrs May splices up the government, it is the Foreign Office that has the skills and experience to make that a reality. Yet by appointing Mr Johnson, the new prime minister has essentially downgraded the department to a tool of domestic political management; a means of keeping the likes of Mr Redwood happy. It is like putting a baboon at the wheel of the Rolls Royce. Sure, the steering wheel, clutch and accelerator will keep the baboon happy and busy. But the price in collateral damage could be high.