LONDON – Britain's next leader will either be Boris Johnson, regarded as an eccentric, gaffe-prone populist who draws comparisons to President Donald Trump, or Jeremy Hunt, who has a reputation as a steady pair of hands, but whose commitment to delivering the country's exit from the European Union – Brexit – has been questioned.

The winner – chosen by an internal Conservative Party vote because Britain elects a party not a prime minster – is expected to be announced on Tuesday.

On Wednesday, current Prime Minister Theresa May will formally submit her resignation to Queen Elizabeth II at Buckingham Palace. May is stepping down over her failed Brexit plan. She will remain a member of Parliament for now.

Here's what you need to know about the candidates, what the new leader could mean for Brexit and Britain's relationship with its closest ally: the United States.

Johnson: self-described 'three-toed sloth'

New York-born Johnson, 55, is the front runner to become Britain's next prime minister.

He is a direct descendant of King George II – his full name is Alexander Boris de Pfeffel Johnson. Johnson has passed through many of the hallowed corridors of the British establishment, including Eton College and Oxford University.

Johnson gave up his U.S. citizenship in 2016 amid a tax probe.

In 2008, he became the second elected mayor of London, a role he used to advance a pro-business, pro-development agenda. Before that, he was a member of Parliament and later served as foreign secretary in May's Cabinet, a position he resigned from, he said at the time, because Brexit's "dream is dying, suffocated by needless self-doubt."

Prior to getting into politics, Johnson was a journalist. He started as a reporter for the Times (of London) but was fired for fabricating a quote. He later edited The Spectator, a longstanding political magazine. His speeches are often laced with allusions to classical civilizations, ribald innuendo and are never far from controversy.

"She's got dyed blonde hair and pouty lips, and a steely blue stare, like a sadistic nurse in a mental hospital," he said of Hilary Clinton in 2007.

As part of his campaign to become London's mayor, Johnson said that "voting (for his Conservative Party) will cause your wife to have bigger breasts and increase your chances of owning a BMW M3."

Johnson has been accused of making racist and Islamophobic remarks and of a general lack of seriousness, whether in terms of the risks of Brexit or in saying the wrong thing, at the wrong time, such as when he falsely claimed that Nazanin Zaghari-Ratcliffe, a British-Iranian national jailed in Iran since 2016 on spying charges, was "teaching people journalism." His remarks were used against the mother-of-one in her trial, which the British government regards as a sham.

Johnson is infatuated with Winston Churchill, the cigar-chomping British politician. He wrote a book about him, published in 2014. In "The Churchill Factor: How One Man Made History," Johnson writes: "No normal family man produces more published words than Shakespeare and Dickens, combined, wins the Nobel Prize for literature, kills umpteen people in armed conflict on four continents, serves in every great office of state including Prime Minister (twice), is indispensable to victory in two world wars and then posthumously sells his paintings for a million dollars."

One of Johnson's tactics as a politician is quintessentially British: self-deprecating humor. In an interview with USA TODAY around the time of the publication of his Churchill book, Johnson played down his similarities to Churchill: both started their careers as journalists, both have U.S. roots, writers both, political mavericks both.

"I am not worthy to lose the latchet of his shoes. I have more in common with a three-toed sloth or a one-eyed pterodactyl or a Kalamata olive than I have with Winston Churchill," he said. Johnson also said in that same interview that his chance of one day becoming, like his hero Churchill, British prime minister was about as good as finding Elvis on Mars or being reincarnated as an olive.

"Boris Johnson is unpredictable," said Richard Whitman, a professor of politics at the University of Kent, in England. "Based on his track record as London's mayor and his campaigning style it's difficult to know beyond Brexit what he might want to achieve as prime minister. It could be a matter of style over substance."

Whitman described Johnson as a "maverick."

Like Hunt, Johnson's Conservative vision for Britain beyond the issue of Brexit is fairly traditional: cut taxes and red tape to stimulate economic growth. Both men are socially liberal on issues from abortion rights to gender discrimination.

Hunt: 'My wife's Japanese.' (She's Chinese)

Hunt, 52, has described himself as a "born-again-Brexiteer" because while he voted for Britain to stay in the EU in the 2016 referendum, given the result, he is now committed to ensuring it takes place on a point of principle: otherwise, he has said, democracy is subverted. It would also be "political suicide" for the Conservative Party to renege on its Brexit promise, Hunt has argued. If Brexit does not happen, he and Johnson both believe, Nigel Farage's single-issue Brexit Party and Jeremy Corbyn's Labour Party are waiting in the wings to potentially put the Conservative Party into exile for years.

Like Johnson, Hunt is the product of elite British institutions. He studied philosophy, politics and economics at Magdalen College, Oxford.

He attended Charterhouse School, a famous boarding school that dates to 1611 and was founded on the grounds of an old Carthusian monastery. Its former pupils are known as Old Carthusians. It only became fully co-ed for boys and girls in 2017.

Hunt has attempted to distinguish his candidacy by highlighting his career in business. Prior to entering politics, he worked first an English teacher in Japan, and then as an entrepreneur who started and sold a public relations consultancy and educational publisher that would later make him one of the wealthiest members of May's Cabinet.

He is often described as "managerial" in his approach to political decisions. Tim Bale, a professor of politics at Queen Mary, University of London, said that if Johnson resembles Trump in his outspokenness and ability to court controversy, then Hunt is the "Mitt Romney of British politics," a reference to the U.S. Senator from Utah's solid, professional demeanor that lacks the special political sauce called charisma.

Hunt's rise in politics was partly enabled by former Prime Minister David Cameron, who called the Brexit vote and then abruptly resigned when it went against him. Hunt attended Oxford University at the same time as Cameron and the latter subsequently appointed him culture secretary when he became prime minister in 2010.

But it was as Britain's longest-serving health secretary, presiding over the country's beloved state-run National Health Service (NHS), that Hunt made his name. Hunt oversaw a series of aggressive reforms to the NHS aimed at boosting its budget, improving inefficiencies and lowering waiting times that his critics fear have come at the cost of opening up the taxpayer-funded service to private companies.

Hunt was named foreign secretary by May after Johnson's resignation. He often uses the fact that his wife is Chinese and he has three half-Chinese children with her to burnish his internationalist credentials.

Not as prone to awkward and insensitive remarks as Johnson, Hunt is not entirely gaffe-free. During his debut trip to China last year as Britain’s new foreign minister he accidentally referred to his wife as "Japanese," an attempt, perhaps, to curry favor with his Chinese hosts. "My wife is Japanese – my wife is Chinese. That’s a terrible mistake to make," Hunt told his counterpart, Chinese Foreign Minister Wang Yi.

"Hunt is someone who has been promoted very swiftly, and very fortuitously, and he sees an opportunity to be the anti-Boris; not openly charismatic, the steady one," said Matt Beech, a director of the Center for British Politics at the University of Hull, in England. "He's leaving all the froth, charisma and personality to one side because he can't compete with Boris, and nor would he want to. His temperament is too different."

Whither Brexit?

Johnson has pledged that if he becomes prime minister he will ensure that Britain departs the EU by October 31, even if that means leaving the 28-nation bloc without a formal exit arrangement. Yet it remains unclear whether British parliamentarians, who repeatedly voted down May's EU exit deal, will let a so-called no-deal Brexit take place because it could significantly harm Britain's economy; cause major disruptions at airports, sea ports and other borders; and risks disrupting many just-in-time supply-chain processes affecting fresh foods and essential medicines. Johnson has raised the prospect of bypassing Parliament to deliver a "no-deal" Brexit if necessary.

More:Britain's embattled leader Theresa May resigns amid Brexit deadlock

"Boris Johnson's commitment to delivering Brexit by Oct. 31 is absolute. He knows if he doesn't, he will be finished," said Iain Duncan Smith, a Johnson supporter and former leader of the Conservative Party. "Hunt is not committed to that date. He wants more wiggle room. This difference is singular because if Johnson wins, the first 100 days of his leadership will be all about leaving the European Union."

Hunt has published a 10-point Brexit delivery plan that includes ramping up preparations for a "no-deal" Brexit, including a "no deal" Cabinet task force. However, he has avoided the "do or die" stance advocated by Johnson and sees leaving the EU without an exit deal as a measure of extreme last resort. This is, ultimately, one of the reasons why he is likely to lose the race against Johnson.

The majority of the British public oppose a "no deal" Brexit, but the majority of Conservative Party members – the 160,000 people who are deciding between Johnson and Hunt – are solidly in favor of a "no deal" Brexit."

Britain's Parliament has taken steps to try to block any attempt by Johnson to go around lawmakers in a quest for a "no-deal" Brexit. A number of May's Cabinet members, including Philip Hammond, her powerful chancellor of the exchequer – a job akin to treasury secretary – have vowed to resign if Johnson becomes prime minister because of the dangers of leaving the EU without a deal.

Meanwhile, EU leaders say they are not willing to renegotiate the terms of an exit deal already agreed upon with May, and which ultimately led to her ouster. This, too, favors Johnson, who Conservative Party members see as far more likely to deliver on his Brexit promise, even if it means a hardline "no deal" version, according to Bale, the professor of politics at Queen Mary, University of London.

What about the Trump factor?

During his state visit to Britain in June, Trump said that Johnson and Hunt would both make good prime ministers to replace May.

"I know Boris, I like him, I've liked him for a long time. I think he would do a very good job," he told a news conference, standing alongside May, and in front of Hunt.

"I know Jeremy, I think he’d do a very good job," he said.

That was before Britain's ambassador to Washington, Sir Kim Darroch, resigned this month after leaked diplomatic cables he sent back to London described the Trump administration as "inept" and "clumsy." The leak led to a fierce backlash from Trump, who said he was no longer willing to see or work with Darroch.

Johnson has attempted to be equivocal about the diplomatic spat, whereas Hunt has expressed strong disapproval, calling Trump "disrespectful and wrong" over the diplomat's treatment. Trump reiterated his support for Johnson's candidacy over the weekend. "I think we're going to have a great relationship," he said.

Both men have ruled out joining any theoretical Trump push to war with Iran over its nuclear program, although whoever wins will face the immediate problem of how to respond to Iran's seizing in the Strait of Hormuz of a British-flagged oil tanker.

Both men have criticized Trump's attacks on Democratic congresswomen.

Whitman, the politics expert at the University of Kent, said if Johnson wins, the first Trump-Johnson press conference "will be fascinating to watch because they are both showmen." He said in terms of the underlying "special relationship" between the U.S. and Britain – forged over decades of close economic and military ties – neither Johnson nor Hunt would dramatically change the flavor of Britain's U.S. partnership.

That assessment was endorsed by Beech, the director of the Center for British Politics.

He said that while Johnson won't back or support everything Trump says or tweets, and temperamentally both men were politically "idiosyncratic" and "instinctive," it didn't really matter whether it was him or Hunt who occupies No. 10 Downing Street, the prime minister's official residence and office in central London.

Beech said that when "it all boils down," Johnson, like Hunt, May, Cameron and other senior mainstream British politicians of recent years, "all realize" they need to get on with the world's most powerful nation and leader. They need to get on with Trump.

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