A U.K. Succession Drama: Who Will Be the Next Ambassador to the U.S.?

In the hectic four-and-a-half years she has served as Britain’s ambassador to the United States, Karen Pierce has overseen a costly renovation of her baronial Washington residence and confronted an American political system in comparable need of repair. The house, at least, is finished.

With Ms. Pierce’s term scheduled to end early next year, Britain’s Labour government now faces a personnel decision that would test the most adroit of diplomats: who to appoint as the next envoy to a country that is a reliable ally but will be on a very different political trajectory, depending on whether Vice President Kamala Harris or former President Donald J. Trump is elected.

Prime Minister Keir Starmer is expected to deal with that uncertainty by not choosing Ms. Pierce’s replacement until after the election in November. That has not stopped the London papers from speculating about who might get what is regarded as the plummiest post in the British diplomatic corps.

Among the names being floated are David Miliband, a former foreign secretary once viewed as a future Labour Party leader; Peter Mandelson, a Labour grandee who has held multiple cabinet posts; and Jonathan Powell, who served as chief of staff to Prime Minister Tony Blair.

“If Kamala Harris wins, he might want a high-profile political ally who can work closely with Democratic leaders,” said Peter Westmacott, ambassador during the comparatively calm years of the Obama administration. “But Starmer tends to prefer substance over personality, so might he prefer a lower-key professional who wouldn’t risk becoming the story?”

If Mr. Trump wins, however, an unorthodox approach might make sense, he said, given the challenges of dealing with an undiplomatic president. “Why not ask Karen Pierce to stay on, since she has the relationships?” Mr. Westmacott suggested.

A career diplomat who has served in Afghanistan, the Balkans and at the United Nations, Ms. Pierce, 64, is equally at home discussing Taliban insurgents, Russian military movements in Ukraine or the swing-state politics of Pennsylvania. She is also, by all accounts, an effervescent party host, who has cultivated ties with high-level Democrats as well as people in Mr. Trump’s orbit.

“She manages to bring people from both parties together, sometimes in the same room,” said Sally Quinn, the journalist and longtime Washington social figure. And, Ms. Quinn added, “Look out when she’s on the dance floor.”

Francesca Craig, who was Ms. Pierce’s social secretary, said her hats and flowery dresses were merely “plumage” for “one of the canniest, insightful, intelligent people I’ve ever worked for. She knows how to wield soft power.”

British diplomats credit Ms. Pierce with playing a role in brokering a dinner in April for the then foreign secretary, David Cameron, with Mr. Trump at his Palm Beach, Fla. estate, Mar-a-Lago, during which Mr. Cameron pressed him not to urge fellow Republicans to block military aid to Ukraine (Congress later approved the aid).

But she also has connections on the other side of the political aisle. Ms. Pierce and her husband, Charles Roxburgh, were invited by Ms. Harris and her husband, Doug Emhoff, to a party last year celebrating 50 years of hip-hop.

The vice president’s residence is next door to Ms. Pierce’s Queen Anne-style mansion on Washington’s embassy row; the ambassador described Ms. Harris and Mr. Emhoff as “very nice neighbors” during a panel discussion last month at the Democratic National Convention, hosted by Politico.

Ms. Pierce was discreet about whether she and the vice president engaged on policy. “It’s quite hard to talk about foreign policy during hip-hop,” she said. “It doesn’t kind of lend itself to that discussion.”

Ms. Pierce, who declined to comment for this article, gets a lot of credit in Washington for her bipartisan approach, although some of her fellow ambassadors noted that she was simply doing the job of a professional diplomat.

Daniel Mulhall, who served as Ireland’s ambassador to Washington from 2017 to 2022, said that while Ms. Pierce “did really cut a dash in Washington,” she exemplified Britain’s practice of sending career diplomats, rather than political appointees, to the United States. The last time it sent a political ambassador was in 1977, appointing Peter Jay, a journalist and the son-in-law of a Labour prime minister, James Callaghan.

The United States, by contrast, almost exclusively sends political appointees to London. They are typically heavyweight political donors, like Mr. Trump’s ambassador, Robert Wood Johnson IV, the billionaire pharmaceutical heir and owner of the New York Jets, or the current ambassador, Jane D. Hartley, a well-connected Democratic fund-raiser who is close to President Biden.

Some British diplomats argue that in Washington’s polarized political and media culture, a seasoned political figure could have an advantage. “I’d advise the foreign secretary that whoever you send, they need to be good on Fox,” said Simon McDonald, a former head of the British diplomatic service.

But Mr. McDonald said the government had to balance those skills with the imperative of not antagonizing the new president, especially if it is Mr. Trump. “Appointing a Labour politician as a Republican president is coming into office might be seen as a little in-your-face,” he said.

The last time Mr. Trump was in office, he suggested that his friend Nigel Farage, the right-wing populist who championed Brexit, would make a fine ambassador. Mr. Trump fell out with the actual envoy, Kim Darroch, after the leak of confidential cables in which Mr. Darroch wrote that the president “radiates insecurity.” When an aggrieved Mr. Trump said he would no longer deal with Mr. Darroch, he resigned.

While his experience was unusual and extreme, Mr. Darroch said an ambassador’s job requires delivering unwelcome news to foreign governments. He questioned whether a political figure could be counted on to do that.

A second Trump term would pose thorny challenges to any ambassador, Mr. Darrroch said, especially one representing a Labour government. But even a victory by Ms. Harris would not guarantee uninterrupted harmony. There is ample precedent, from Ronald Reagan’s invasion of Grenada to the NATO military intervention in Kosovo, for the two sides to disagree even if their leaders are ideologically aligned.

“It’s a bit better with a Labour government and the Democrats,” Mr. Darroch said. “But this only goes so far. In the end, there’s a bit of ‘America First’ in every U.S. administration.”