The path to the 2024 US presidential election begins almost as soon as midterm elections end – and several candidates are already waiting in the wings.
Former president Donald Trump is currently favoured to win the party’s nominating contest and go on to face President Joe Biden in a rematch of their 2020 race.
But while Mr Trump remains hugely popular with Republican voters, he faces numerous legal challenges and will also be 78 years old in two years.
That means he may be in for a stiff challenge from a coterie of Republican hopefuls, including some who once backed him.
Ron DeSantis
Florida Governor Ron DeSantis has worked hard to emulate Mr Trump and he is widely considered the candidate most likely to supplant him.
At 44 years old, the Harvard and Yale-educated lawyer is a relative newcomer in US politics.
He once served in the US Navy, including a tour in Iraq. He also served in the House of Representatives from 2013 to 2018.
But his star has risen considerably since he became Florida governor in 2019, a role in which he positions himself as an enthusiastic champion of conservativism.
He eschewed mask and vaccine mandates during the pandemic, signed anti-riot laws in the wake of racial justice protests and backed legislation to limit LGBT education in primary schools.
Under DeSantis’ tenure, Republican voters outnumber Democrats in the state for the first time – and he is expected to coast to re-election on Tuesday.
His chief rival appears to be paying very close attention.
Mr Trump recently held a rally in Florida but snubbed the governor. And at a rally on Saturday, Mr Trump showed the crowd poll numbers favourable to himself and referred to Mr DeSantis as “Ron DeSanctimonious”- though he later endorsed him on Monday night while also hinting at his own run for the presidency in 2024.
Mike Pence
For four years, Mike Pence was a loyal deputy to Mr Trump as his vice-president – until last year’s Capitol riot splintered their relationship.
The son of a Korean War veteran, Mr Pence began his career in conservative politics as a talk radio host.
He was elected to the House in 2000 and served until 2013, describing himself as a “principled conservative” and aligning with the Tea Party movement.
He also served as governor of Indiana from 2013 to 2017. In that role, he passed the largest tax cut in state history, and signed bills to restrict abortion and protect religious freedom.
Mr Pence, 63, is a born-again evangelical Catholic and his addition to the 2016 presidential ticket is credited with helping turn out evangelical Christians, a crucial voting bloc, for Mr Trump.
Calm and soft-spoken, he was seen as an effective surrogate to the bomb-throwing Donald. But Mr Trump turned on him for lacking “courage” after he refused to help overturn the 2020 election results.
Pro-Trump rioters stormed the US Capitol in January 2021 and were heard chanting “Hang Mike Pence!”. At one point, they were reportedly within 40ft (12m) of the vice-president.
The two have kept their distance since then, with Mr Pence endorsing several Republican candidates this year, including Georgia Governor Brian Kemp, whose opponent Mr Trump backed. But Mr Pence has never directly criticised his old boss.
Liz Cheney
The daughter of former vice-president Dick Cheney was once a rising star in the Republican Party, serving as its third-highest ranking member in the House from 2019 to 2021.
A fiscal and social conservative with interventionist foreign policy views, she won her father’s old seat in 2017, going on to represent Wyoming in Congress, and voted in lockstep with the Trump administration.
But she fell out of favour with Republicans after repeatedly criticising Mr Trump and then voting to impeach him for his role in the 6 January Capitol riots.
She was dumped from her leadership post, formally reprimanded and is no longer recognised by the Wyoming Republican Party.
Ms Cheney, 56, went on to become one of only two Republicans on the congressional committee investigating the Capitol riots. As vice-chair, she has led the charge to hold Mr Trump and others accountable.
The role cost her her job this August, with the former president endorsing an opponent who thrashed her by a near-40% margin in the Wyoming primary race.
But Ms Cheney still considers herself a Republican, vowing to do whatever she must “to help restore our party”.
Mike Pompeo
As a congressman from Kansas, Mike Pompeo issued a stark warning in 2016 that Mr Trump would be “an authoritarian president who ignored our Constitution”.
An Army veteran who graduated first in his class from the prestigious West Point military academy, he served in the House between 2011 and 2017.
The Harvard-educated lawyer would go on to serve as CIA director and secretary of state in the Trump administration.
He played a role in major US foreign policy overtures, from helping plan Mr Trump’s summits with North Korea’s Kim Jong-un to helping overturn decades of US policy toward Israel. But he also courted controversy, including clashes with reporters and at least two ethics investigations.
Glenn Youngkin
Glenn Youngkin thrilled the Republican Party when he won the governor’s race in Virginia last year. A political novice who spent 25 years at the Carlyle Group private equity firm, he beat a man who had been in Democratic politics since the 1980s.
In a state that has trended toward Democrats in recent years, Mr Youngkin criticised partisan politics as “too toxic” and campaigned on a tone of bipartisanship.
But the 55-year-old has waded into hot-button topics since his first day in charge, from revoking the state’s Covid-19 restrictions to banning the teaching of critical race theory in schools.
He has supported Republicans around the country in this election. At a campaign stop last month, he drew criticism for making light of the violent assault of House Speaker Nancy Pelosi’s husband and later apologised.
Nikki Haley
Once considered one of the Republican Party’s brightest young prospects, Nikki Haley has seen her star dim considerably in recent years.
Born in South Carolina to Punjabi Sikh immigrants, Ms Haley became the youngest governor in the country in 2009. She earned national attention in 2015 after calling for the removal of the Confederate flag from the South Carolina Capitol.
Despite saying she was “not a fan” of Mr Trump in 2016, she later accepted his nomination to be the US ambassador to the United Nations, a tenure marked by her dramatic exit from a UN Security Council meeting as a Palestinian envoy was speaking.
Ms Haley, 50, has waffled on whether she still supports Mr Trump, and has drawn many critics in the process. Mr Trump reportedly refused to even meet with her last year.
Rick Scott
Rick Scott, a 69-year-old lawmaker from Florida, was tasked with helping Republicans win back the Senate this year.
It was a role in which he raised a lot of money, supported candidates all around the country and boosted engagement with minority voters.
A former two-term Florida governor, he has been under fire from Democrats recently after proposing major reductions in the size of the federal government.
Others who could run
Tim Scott: The 57-year-old from South Carolina is the first African-American politician to serve in both chambers of Congress and is the first black Republican Senator since 1979.
Ted Cruz: The senator from Texas, 51, made a strong showing in the Republican primary for the 2016 presidential election before placing second behind Mr Trump.
Larry Hogan: A skin cancer survivor, the moderate 66-year-old Republican has served as governor of Maryland – a Democrat-friendly state – since 2015.
Greg Abbott: The first Texas governor to use a wheelchair, Mr Abbott, 64, has championed conservative policies since his election in 2014.
Kristi Noem: South Dakota’s first female governor garnered national attention with her opposition to Covid restrictions and has been eager to wade into national conversations.