The political bromance between Boris Johnson and Donald Trump leaves Britain and its transatlantic "special relationship" exposed if Joe Biden wins next week, just as the country needs all the friends it can get.
The UK is divorcing the European Union and looking to revitalise partnerships elsewhere, but has managed to antagonise Trump's Democratic opponent over its Brexit plans for Northern Ireland.
French President Emmanuel Macron has at times also strived to keep Trump close. But the British prime minister is more closely associated with his fellow convention-shredding populist in Washington.
"There is a lot of frantic repositioning going on at the moment here in London by this administration in Britain," former Conservative finance minister George Osborne told CNN on Sunday.
"But I don't think Joe Biden will feel particularly warmly toward this British government, and they're going to have to work very hard to change that," he said.
Last December, as Johnson closed in on a general election victory, Biden showed his disdain in describing the Conservative politician as a "physical and emotional clone" of Trump.
The president has himself praised Johnson as "Britain('s) Trump", and the prime minister's own long trail of provocative comments has come back to haunt him.
Biden was vice president to Barack Obama when Johnson, in 2016, wrote that Obama was anti-UK owing to his "part-Kenyan" heritage and "ancestral dislike of the British Empire".
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That remark was highlighted recently on Twitter by Obama's deputy national security adviser, Ben Rhodes, who sees Johnson as Trump "with better hair" and a higher IQ. Many veterans of the Obama administration are likely to populate a Biden White House.
If elected, it will be up to Biden and his team to decide whether "to litigate and punish the past or focus on the future", according to Heather Conley, director of the Europe programme at the Center for Strategic and International Studies in Washington.
"I am comforted that populists are chameleons: they take on the hue of the political moment. I trust should vice president Biden win, Mr Johnson's hue will change dramatically," she told AFP.
Trump's relationship with previous British prime minister Theresa May was awful. But he was effusive about the New York-born Johnson when the "tough" and "smart" former foreign secretary replaced her last year.
Johnson in turn has lauded Trump's "many, many good qualities", in marked contrast to the arm's-length mistrust displayed by others such as German Chancellor Angela Merkel.
Yet Britain, next year's president of the G7, remains far more aligned with France and Germany -- as well as Biden -- on climate change, Iran, Russia and collective defence under the NATO umbrella.
A post-Brexit US-UK trade deal is still a work in progress under Trump, who characteristically is said to be driving a hard bargain after slapping tariffs on Scottish whisky amid a wider spat with the EU.
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Conley said that Biden, as a "dedicated transatlanticist", was likely to resolve Trump's trade row with the EU and Britain, as part of a wider fence-mending policy if elected.
"But certainly issues related to Brexit are going to be addressed much differently in a Biden administration than the Brexit enthusiasm of the Trump administration -- and even that hasn't been easy going," the expert added.
The US-UK trade negotiation has been attracting close attention from Democrats, since Johnson in September introduced legislation that unilaterally strips Brussels of a role in regulating future trade between Northern Ireland and EU member Ireland.
Biden, who speaks passionately of his Irish roots, warned that the trade deal would be dead on arrival if Britain, via its Brexit policy, undermines Northern Ireland's Good Friday peace agreement.
Johnson on Monday said the United States was Britain's "closest and most important ally", but refused to take sides in the November 3 election. Some Conservatives are showing no such reserve.
In 1992, Johnson's former finance minister Sajid Javid moved to New York to work as a banker. Writing in the Daily Telegraph last week, he reflected on hearing Ronald Reagan's final speech to the Republican convention that summer.
The former president appealed to "your best hopes, not your worst fears", Javid said.
"Only one of the candidates can credibly say the same. Britain is better off with Biden."