LONDON — Few world leaders have felt the fallout of President-elect Joe Biden’s victory more quickly than Prime Minister Boris Johnson.
Mr. Johnson is in the final phases of trying to negotiate a post-Brexit trade agreement with the European Union, a complex challenge that just became more urgent with the defeat of his ally and ideological mate, President Trump.
A failed negotiation with Brussels could stir up tensions between Mr. Johnson and Mr. Biden even before they get to know each other, because it would almost certainly reverberate badly in Ireland. Mr. Biden, who speaks often and fondly of his Irish roots, has already warned Mr. Johnson not to do anything in his trade negotiations that would threaten peace in Northern Ireland.
“The election completely changed the game,” said Mujtaba Rahman, an analyst at the political risk consultancy, Eurasia Group.
Unlike Mr. Trump, Mr. Biden opposed Brexit. He is not likely to make a trade deal with London as high a priority as Mr. Trump might have. And he has ruled out such a deal altogether if Britain does anything to water down the protections of Northern Ireland that are enshrined in the Withdrawal Agreement, which set the stage for Britain’s formal departure from the European Union last January.
“If the government doesn’t deliver an E.U. deal and refuses to implement the Withdrawal Agreement,” Mr. Rahman said, “the first discussion Boris Johnson will have with Joe Biden is a row over Northern Ireland.”
British newspapers have been full of stories in recent days raising alarm about the future of the “special relationship” between Britain and the United States, and musing about whether Mr. Johnson and Mr. Biden, who have yet to meet, are destined to be at odds.
After Mr. Johnson congratulated Mr. Biden and Vice President-elect Kamala Harris on their election, a former White House aide to Barack Obama, Tommy Vietor, said on Twitter, “This shapeshifting creep weighs in. We will never forget your racist comments about Obama and slavish devotion to Trump.”
In 2016, when Mr. Johnson was mayor of London, he noted that Mr. Obama had replaced a bust of Winston Churchill in the Oval Office with one of Martin Luther King Jr. and attributed it to “the part-Kenyan president’s ancestral dislike of the British Empire.” He also once likened Hillary Clinton to Lady Macbeth.
“The comments Boris Johnson has made about Barack Obama and Hillary Clinton, who are regarded as family in Biden-land, have not been forgotten, and can’t be brushed aside with a joke,” said Peter Westmacott, a former British ambassador to Washington. “The same goes for his bromance with Donald Trump.”
British officials are steeling themselves for symbolic snubs, like having Mr. Biden call the prime minister of Ireland before Mr. Johnson or making his first European visit as president to Paris, Berlin or Brussels rather than London.
Mr. Johnson’s political dilemma was cast into sharp relief on Monday when Britain’s House of Lords voted down by a large margin clauses in legislation introduced by his government that would rewrite the parts of the Withdrawal Agreement that deal with Northern Ireland. Critics warn that these revisions could lead to the resurrection of a hard border across Ireland and jeopardize the Good Friday Agreement, which ended years of sectarian violence.
For now, the government insists it will push through the legislation in the House of Commons, where Mr. Johnson has an 80-seat majority. As a practical matter, there is little the unelected House of Lords can do to block it since, by convention, the Commons can overturn a vote by the Lords.
Downing Street argues that the new legislation, which is known as the Internal Market Bill and aims to insure that trade flows freely between Britain and Northern Ireland, is a safety net in case there is no trade deal. But it is also popular with hard-line Brexiteers in Mr. Johnson’s Conservative Party, who view it as an assertion of British sovereignty, even as members of the Cabinet admit that it breaks international law.
Britain hoped to use the threat of the legislation, analysts said, as leverage to extract better trade terms from the European Union. But the change in power at the White House has scrambled that calculation. Mr. Johnson now must balance his determination to pressure Brussels with his desire not to antagonize Mr. Biden. European officials, well aware of this, now hold the upper hand.
“He’s even more trapped than he was before,” said David Henig, director of the U.K. Trade Policy Project at the European Center for International Political Economy, a research institute. “This administration is unsure which way to turn, even when faced with a clearly changed dynamic.”
Battered by the economic upheaval from the coronavirus pandemic, British businesses are desperate for a trade agreement that would limit further disruption in January when the country quits Europe’s trading system.
Time is running out if an agreement is to be ratified by the European and British Parliaments before the Dec. 31 deadline. There are still significant gaps between the two sides on issues like fishing rights, state aid rules, guarantees of fair market competition and ways to solve future disputes.
Still, Mr. Johnson is viewed as eager to strike a deal. If he comes to terms with Brussels, the government could simply leave the offending clauses out of the Internal Market Bill when it comes back to the House of Commons next month.
The question, Mr. Henig said, was whether Mr. Johnson was willing to lean far enough toward the other side to bridge the gap between “the imagined deal he hopes he can make, and the real deal on offer.”
Analysts said the biggest worry was about how the new calculus would affect France, traditionally the most hard-line country on Brexit trade issues. The French president, Emmanuel Macron, faces his own election in 2022, and France’s negotiation with Britain on fishing rights is politically resonant at home.
If France plays hard ball and Mr. Johnson is viewed as caving in, he would face the wrath of some Conservative Party lawmakers, who are already angry over coronavirus lockdown rules and a succession of embarrassing policy reversals.
As for Mr. Biden, the antipathy of some people who work for him toward Mr. Johnson is genuine, according to former officials. But American and British diplomats both said the fears of a clash between the two men were overblown, in part because of the shared interest of two close allies.
”The Obama and Biden people clearly do despise Boris Johnson,” said Jeremy Shapiro, a former Obama administration official who is the research director of the European Center on Foreign Relations in London. “But so what?”
“They support the idea of allies, particularly European ones, and want to show the world and the American people that they can garner respect in the world that Trump could not,” Mr. Shapiro said. “The U.K. is central to that in the American mind.”