When then-presidential candidate Donald Trump announced in August 2016 that “they will soon be calling me MR. BREXIT,” few took him seriously.

Three years on — and after many more related Trump remarks, now as U.S. president — there were no laughs Monday when British opposition leader Jeremy Corbyn warned of a “Trump-deal Brexit,” a reference to Trump’s repeated offers of a post-Brexit trade deal between the United States and Britain. Such an agreement, Corbyn argued, would lead to “a one-sided United States trade deal that will put us at the mercy of Donald Trump and the biggest American corporations.”

Even as the Brexit battle heats up — with Prime Minister Boris Johnson, a Conservative, planning to suspend Parliament next week and threatening to expel rebellious Conservative members of Parliament from the party — Trump has managed to keep inserting himself into the Brexit debate.

But has he managed to persuade Brits to take his remarks seriously? British analysts aren’t so sure.

“Nobody really takes him entirely literally,” said David Henig, director of the U.K. Trade Policy Project at the European Center for International Political Economy.

In his address Monday, Corbyn was referring to a no-deal Brexit, under which ties between continental Europe and Britain would be abruptly cut without arrangements in place to alleviate the impact — a scenario that appears increasingly possible under Johnson. The Corbyn-led Labour Party and other Brexit critics argue that such an abrupt exit from the European Union would trigger food and drug shortages and force Britain into trade talks with the United States from a weakened negotiating position.

Those concerns are partially motivated by Trump’s remarks. In June, the president suggested that Britain’s National Health Service would be part of any post-Brexit trade talks. Although Trump quickly backtracked, British politicians, including those considered close to him, continue to express opposition to the idea.

Johnson said in July that he would “under no circumstances” agree to put the NHS up for sale.

Analysts have questioned how much sway Trump would have over a trade deal, even if he was serious about it.

“The power that the president has to sort of force [a trade deal] into being by sheer force of will is actually fairly limited,” said Jacob Parakilas, a consultant and former deputy head of the U.S. and the Americas program at the London-based Chatham House think tank.

House Speaker Nancy Pelosi (D-Calif.) warned this year that Congress would block any trade deals with Britain if the British government were to weaken the Northern Ireland peace pact known as the Good Friday Agreement.

That hurdle had already doomed then-British Prime Minister Theresa May’s Brexit agreement with the E.U., which was designed in a way that would have upheld the peace pact by keeping border controls suspended. It also would have tied Britain to the E.U. to a greater extent than hard-line Brexiteers were willing to agree to. May was unable to get Parliament to approve her deal, and she ultimately resigned.

Trump started to lash out at May’s more moderate Brexit strategy early on in his term and advocated in favor of the more hard-line approach backed by Johnson — a fellow Conservative and rival of May — and others.

In an interview with the Sun tabloid, published while he was in Britain for talks with May last year, Trump praised Johnson as someone who would make a “great prime minister” and complained that May “didn’t listen” to his Brexit advice. (May later told the BBC that Trump advised her to “sue the E.U. — not go into negotiations.”)

Her more moderate plans, which would have preserved a number of economic ties to the E.U., would become a hurdle for any U.S.-Britain trade talks, Trump warned in his interview with the Sun, as the United States would be “dealing with the European Union instead of dealing with the U.K.”

In Johnson, Trump appears to have found a more receptive ally. In June, Trump suggested that Britain should refuse to pay the E.U. its $47 billion divorce bill in case of a no-deal Brexit. Johnson took a similar stance in August.

Although that move may charm Trump, it would risk further disgruntling E.U. leaders.

The E.U. also has warned that Johnson’s hard-line approach is jeopardizing the very Northern Ireland peace pact that the European Union and Pelosi are seeking to preserve at all costs, which would make congressional approval for a U.S.-Britain trade deal improbable — unless Republicans win the House and the Senate next year.

“Trump has seized this sort of moment in world politics as the rise of the nationalists, and I think he sees some of the leading figures behind Brexit as having a similarly nationalistic view of the world,” Parakilas said.

The problem is that “creating an alliance with nationalists is ultimately a fairly unsteady prospect because the point of nationalism is you put your nation’s interests first,” he said.

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