One hundred and 40 years ago, a great English humorist met America’s most loved elephant and declared they would both go down in history because true fame comes when you are known by one name of five letters. Jumbo, star attraction in P. T. Barnum’s circus, would be a name no one would ever forget, claimed Oscar Wilde, just like Jesus and Plato. Or, as came later, Elvis, Boris, and Trump.

This September, some 150,000 people in Britain will consider which politician with a memorable five-letter name they want to be their prime minister. Are they “Ready for Rishi,” to quote the campaign slogan of the man whose resignation as chancellor brought about the end of Boris Johnson, or do they “trust in Truss”?

“Trust in Truss” or “ready for Rishi”?

The selection of the 15th prime minister of Elizabeth II’s 70-year reign could not be more different from her second. In 1955, Sir Winston Churchill told the Queen over dinner that he was resigning and that Sir Anthony Eden, his heir apparent for 15 years, would take over. There was no contest and little debate, though Churchill told his private secretary that night that he feared Eden wouldn’t be up to it: the new leader was sworn in the next day, appointed a new Cabinet, most of whom had gone to the same school as he had, and called an immediate election, which he won. He lasted less than two years in Downing Street.

Britain’s next prime minister may also get only two years in the job—the next election can be held anytime between now and January 2025, and the Conservatives are trailing Labour in the polls—but the candidates will have undergone a thorough and bruising eight-week selection process before the decision is made, on September 5. Eleven M.P.’s entered the contest and were gradually whittled down by votes of their colleagues to two, who will now spend their summer in hustings around the country, hoping to appeal to 150,000 grassroots Conservative Party members. This is how we choose prime ministers in the age of reality television.

Their choice is between two graduates of Oxford University, like 10 of the Queen’s previous prime ministers, but they come from very different backgrounds. Liz Truss, 47, who would be Britain’s third female prime minister, is from a solidly middle-class left-wing family who moved around the country with her father’s teaching job, settling for her formative years in Yorkshire. She has complained about the quality of the state education she received, saying it made her a Conservative.

Rishi Sunak, one of six candidates in the contest from an ethnic-minority background, would be the first nonwhite prime minister and is believed to be the richest British M.P. there has ever been. His parents sent him to one of Britain’s most exclusive public schools, where he became head boy, and after Oxford he studied at Stanford, where he met and married one of the richest women in India. If he wins, he would be the first prime minister born in the 1980s.

It’s all a game: Boris Johnson and Rishi Sunak in 2020.

Sunak, 42, has soared up the greasy pole since his election in 2015. Only William Pitt the Younger, who became prime minister in 1783 after three years as an M.P., ascended faster. The son of Indian immigrants who worked in health care, Sunak won a place at the exclusive Winchester College before going to Oxford, where being a Euro-skeptic Conservative in the era of Tony Blair passed for rebellion.

He went on to work for Goldman Sachs, where his boss told him he was too nice to go into politics, and also as a hedge-fund manager, on either side of gaining an M.B.A. from Stanford. A City colleague said he “thinks in Excel.” He has a nerdy interest in Star Wars films and can be sweetly naïve, such as when he told an interviewer that he was a “total coke addict,” quickly clarifying on seeing their reaction that he meant Coca-Cola and had seven fillings to show for it.

Are they “ready for Rishi,” to quote the campaign slogan of the man whose resignation as chancellor brought about the end of Boris Johnson, or do they “trust in Truss”?

In 2020, Sunak became the second-youngest Treasury chief since Randolph Churchill, Winston’s father, in 1886. He soon had to turn on the spending taps to deal with the coronavirus, including $400 billion in emergency support for businesses a week after his first budget. A $1 billion subsidy scheme for restaurants, called Eat Out to Help Out, was advertised with Sunak’s signature across the posters. This was the peak of Brand Rishi, when he was the most popular chancellor since 1978.

What goes up, as any economist will tell you, tends to come down. Sunak’s popularity began to sink as he had to find ways to pay for this splurge and the cost-of-living-crisis bit. A rise in personal taxation to pay for health care went down badly, especially when coupled with galloping inflation, and his ratings slumped when it was revealed early in 2022 that his wife, Akshata Murthy, daughter of an Indian software billionaire, was legally avoiding an estimated $24 million in U.K. taxes. Then came the news that, until a year ago, she and her husband had held U.S. green cards, despite living in Downing Street. Sunak’s spokesman said he had not broken any rules.

Sunak’s standing with the Tory grass roots—those who will vote for the prime minister—fell in a year from his being the second-most-popular member of the Cabinet in a monthly poll (out of 32) to just about the least popular at No. 30, and many wrote him off. When the long-expected coup finally came against Johnson, however, Sunak established himself as the first choice of M.P.’s, running on a platform of being a safe pair of hands, while Truss battled to be the choice of the tax-cutting, pro-Brexit wing of the party.

This was quite a transformation for one who had been a very vocal supporter of remaining in the European Union (Sunak had been as strongly in favor of leaving), but Truss’s political career has been on a journey. The daughter of left-wing intellectuals, she spent her youth attending marches against nuclear weapons and chanting for the removal of Margaret Thatcher. At Oxford, she joined the Liberal Democrats and made a speech at their party conference in 1994 calling for the abolition of the monarchy. She moved toward the Conservatives when she trained as an accountant and worked for Shell, becoming a Tory councillor in Greenwich, southeast London. She named a daughter Liberty, echoing George Osborne, the former chancellor.

Head held high: Johnson, left, and Liz Truss, second from right, at a celebration marking Queen Elizabeth II’s Platinum Jubilee.

After failing to be elected to Parliament in 2001 and 2005, Truss was selected to contest the rural seat of South West Norfolk but was nearly removed after the local party discovered she’d had an affair with a married M.P. David Cameron, then the Conservative leader, defended her against the critics, who were dubbed the “Turnip Taliban” because of their strict moral views and the area’s agricultural output, and she was elected in 2010. Four years later, Cameron made her his environment secretary, where she was teased for a clip from her conference speech that went viral online in which she railed against Britain’s importation of cheese. “That. Is. A. Dis. Grace,” she thundered.

After the Brexit referendum, Truss served as justice secretary and as No. 2 at the Treasury but was working on re-inventing herself as a pro-Brexit, low-tax reincarnation of Mrs. Thatcher. She even appeared to model her fashion choices on those of the former prime minister. An early backer of Johnson for leader, along with Sunak, she was rewarded with a promotion to trade secretary and then, last September, to foreign secretary. Though mocked for her enthusiastic self-promotion on Instagram, she was shrewdly building a profile, bolstered by hosting regular “Fizz with Liz” drinks receptions for prospective backers.

Critics accuse Truss of being socially awkward and cold. Dominic Cummings, Johnson’s former chief adviser who fell out spectacularly with his boss, has called her a “human hand grenade.” Supporters say she gets things done and contrast her plan for immediate tax cuts with Sunak’s steady-as-she-goes approach.

Meanwhile, some anti-Borexit Johnson fans still hope the party will return to its fallen leader. Some 10,000 members have signed a petition demanding he be added to the ballot, while others want him to bide his time on the backbenches and await a second chance. His future could be complicated by a Commons inquiry this autumn into whether he misled Parliament over parties in Downing Street during lockdown. If censured, he would face a recall ballot in his constituency to decide if he can remain an M.P.

Johnson is being coy about his future, happy to encourage speculation. First, though, he will be keen to ensure that his income soars. His memoirs will surely be written in record time and receive a record advance, and there is a long-promised biography of William Shakespeare to complete. If Theresa May, a robotic orator, could command $130,000 a time on the public-speaking tour, Johnson will become very rich indeed with his colorful anecdotes. There is even a rumor that he might edit the Evening Standard, a London-based newspaper, given his friendship with the Russian oligarch who owns it. He ended his final question time as prime minister on July 20 by declaring, “Hasta la vista, baby.” That use of an Arnold Schwarzenegger quote was surely designed to leave his audience thinking of another Terminator line: “I’ll be back.”

Patrick Kidd is the editor of the Diary column in The Times of London. A collection of work from his time as parliamentary sketch writer, The Weak Are a Long Time in Politics, was published in 2019