Theresa May's historic summit with President Trump has exposed a serious predicament for her government.

For, defying augury, the British prime minister is out to achieve something improbable. If Britain is going to leave the European Union, May has decided, it will leave decisively, even sacrificing tariff-free access to the single market - Britain's largest export market - and seek its fortune elsewhere.

But if the British state is to put border controls and withdrawal from the European Court of Justice ahead of its major trading relationship with Europe, it will need a world in which it can turn a profit. And for May, that means an American-led world, a "free trade empire" in which US-led multilateral institutions open markets in labour, goods and capital, suppress legal obstacles and defend strong property rights for corporations.

The Trans-Pacific Partnership (TPP), which Trump has overruled with an executive order, would have given new property rights to companies, such as pharmaceuticals, and allowed businesses to sue over environmental and other restrictions to their profit-making. It was worth hundreds of billions to US corporations and would have been a goldmine to anyone who gained access.

Only in this context can May's pivot to "hard Brexit" make sense. The Financial Times pointed out a particular irony in her turning her back on the single market, a model Thatcherite institution. But it has long been a dream of the middle-class right in Britain that it could recover its old colonial elan by shaking off European shackles and becoming a dominant, freewheeling "global trader".

If May could achieve this epochal shift, she would reconcile diverging branches of conservatism, restore the Tories as the dominant party of government, tighten the Atlantic alliance, and use new agreements to drive down labour costs and make British capitalism more competitive.

Her biggest problem is Donald Trump. For, while she likes to sound the odd Trumpian note, she wants America to preserve its long-standing role in managing globalisation. Trump does not. Thus, her trip to the United States, though hedged with grovelling remarks about the president, began with a carefully pitched appeal to Republican elites to hinder Trump's protectionism and nativism.

May-Trump disagreements

In a speech to the Republican Party in Philadelphia, May deployed the word "international" or "internationalist" 12 times and made 22 mentions of "lead" or "leadership". The burden of her appeal was to American exceptionalism and the old imperial ideal of Manifest Destiny.

She claimed, with the self-regard typical of British and American politicians, that the "special relationship" between two predominantly white, English-speaking powers, "made the modern world". Crucially, she warned, "when others step up as we step back, it is bad for America, for Britain and the world." She also defended the UN, and Obama's Iran deal. This was a barely coded plea to Republican elites not to turn towards autarky.

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In a symptomatic move, she also pandered to Republican Sinophobia, citing China as an emerging rival, alongside Russia. On the face of it, this was disingenuous, since her next stop after visiting Trump in the White House was Beijing. May has consistently courted Chinese investors, opposed tariffs on Chinese imports, and even helped fund a Chinese-led Asian investment bank over the objections of the US.

But it could also be seen as a tacit appeal to reprise Obama's "pivot to Asia," of which the TPP was to be a culmination. The TPP would have outflanked Beijing's own attempt to forge a trade pact in the Pacific Rim economies, thus preserving Washington's global dominance against an emerging competitor.

In their press conference, the differences between May and Trump were obvious, though blanketed with diplomatic niceties. May's insistence that sanctions continue to be applied to Russia until the Minsk Agreement is implemented, was met by bluff indifference on Trump's part, who gives the impression he wouldn't know a Minsk from a matchbox.

On Brexit, Trump tried to flatter May, but couldn't even remember the name of the European Union, which he referred to as "the group, I call them the consortium". May almost pleaded with Trump to continue to back NATO against Russia, a plea which Trump met with polite nodding.

Trump's understanding of the relationship between markets and the military was defensive rather than global. Blaming Mexico for beating the US "to a pulp" in trade negotiations, costing "millions and millions of people" their jobs and sending illegal immigrants, he lauded the appointment of General Kelly, formerly of Guantanamo Bay and US Southern Command (the military branch that covers US dominion over South and Cenral America) to Homeland Security. That is, he would resolve supposed market dysfunctions by militarising the border.

May visibly squirmed. If she had hoped Trump was not for real, her best hope now might be that with chaos in the corridors of power, he will soon be replaced by a more conventional Republican leader. Otherwise, her own attempt to have a decaffeinated Trumpism, is set for a calamitous failure.

Richard Seymour is an author and broadcaster based in London. He has written for The Guardian, the London Review of Books and many other publications.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.