The path to the 2024 US presidential election began almost as soon as last November’s midterm elections ended – and several candidates are waiting in the wings.
Former President Donald Trump has announced he will run for the party’s nominating contest, vowing to “make America great and glorious again”.
Mr Trump remains the favourite choice of Republican voters, but his legal troubles and his role in an underwhelming midterm election performance for the party have left him vulnerable.
The ex-president, who will be 78 when the general election begins, could face a stiff challenge from a coterie of Republican hopefuls, including some who once backed him.
Nikki Haley announced her bid for the presidency in mid-February, becoming the first major Republican candidate to commit to taking on Mr Trump.
Once considered one of the Republican Party’s brightest young prospects, Nikki Haley has kept a lower profile 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.
Her campaign, which includes a call for mandatory mental competency tests for politicians over 75 years old, stresses the need for “a new generation” of US leaders.
Florida Governor Ron DeSantis has worked hard to emulate Mr Trump, and is viewed as the candidate most likely to face him in a head-to-head race.
Boosted to the governorship by Mr Trump’s endorsement, he romped to re-election in the midterms by more than 1.5 million votes, the largest margin in the state in more than four decades.
At 44 years old, the Harvard and Yale-educated lawyer is still a relative newcomer in US politics.
He once served in the US Navy, including a tour in Iraq. He was also a little-known member of the House of Representatives from 2013 to 2018.
But Mr DeSantis has seen his star rise considerably since he became governor in 2019, a role in which he positions himself as an enthusiastic champion of conservativism.
He eschewed mask and vaccine mandates during the Covid pandemic, signed anti-riot laws in the wake of racial justice protests, and has backed legislation to limit LGBT education, restrict abortions and loosen gun laws. Under his tenure, Republican voters outnumber Democrats in the state for the first time.
Mr Trump appears to be paying very close attention, recently nicknaming his rival “Ron DeSanctimonious” and even implying on social media that he may be a paedophile.
For four years, Mike Pence was a loyal deputy to Mr Trump as his vice-president – until 2021’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 Christian and his addition to the 2016 presidential ticket is credited with helping turn out evangelicals, 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 largely kept their distance since then, but Mr Pence has been in a delicate dance to avoid alienating Trump-friendly voters.
Vivek Ramaswamy, 37, launched his long-shot White House bid during a late February appearance on the Fox News channel.
An Indian-American biotech entrepreneur with no previous political experience, he is a regular fixture on Fox host Tucker Carlson’s daily programme, the most-watched cable news show in the US.
The Harvard and Yale graduate argues the country is in the midst of a national identity crisis driven by a decline in faith, patriotism and meritocracy.
He ran a pharmaceutical company from 2014 to 2021, then co-founded Strive Asset Management, which shirks the “divisive” environmental, social and corporate governance (ESG) framework and offers itself as an alternative to large firms like Blackrock.
Mr Ramaswamy is also the author of Woke, Inc.: Inside Corporate America’s Social Justice Scam.
Former two-term Arkansas Governor Asa Hutchinson announced his run for president during an April interview with ABC News days after Mr Trump was indicted on criminal charges in New York.
Mr Hutchinson, 72, expressed concern over how the case has played out but called it “a sideshow and distraction” that should prompt Mr Trump to withdraw from the race.
The former attorney and businessman was the youngest federal prosecutor in the nation under the Ronald Reagan administration.
He also served two terms in the US House of Representatives, including as a prosecutor in Bill Clinton’s impeachment trial, and was George W Bush’s Drug Enforcement Administration (DEA) chief.
Referring to himself as a “non-Trump” candidate, he has vowed to lean into “common sense, consistent conservatism”.
Another long-shot contender, Michigan businessman Perry Johnson joined the race in March.
Mr Johnson, 75, spent millions of his own money to run for Michigan governor last year, but was disqualified by the state’s election bureau, which said he forged thousands of nominating signatures.
He is touting a plan to reignite the economy by shaving 2% in federal spending every year.
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.
Since leaving the post, Mr Pompeo has made thinly-veiled criticisms of his former boss, arguing the country needs “serious leaders” who are “not spending all their time thinking about Twitter”.
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”.
Glenn Youngkin thrilled the Republican Party when he won the governor’s race in Virginia in 2021. 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 supported Republicans around the country in the midterm elections. At one campaign stop, he drew criticism for making light of the violent assault of House Speaker Nancy Pelosi’s husband and later apologised.
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.
Greg Abbott: The first Texas governor to use a wheelchair, Mr Abbott, 65, has championed conservative policies since his election in 2014.
Kristi Noem: South Dakota’s first female governor, 51, garnered national attention with her opposition to Covid restrictions and has been eager to wade into national conversations.
Who is not running?
Larry Hogan: A moderate who ran Maryland – a Democrat-friendly state – from 2015 to 2023, Mr Hogan, 66, seriously considered running but said he did not want to be part of a crowded field that helps elect Mr Trump again.
Ted Cruz: The senator from Texas, 52, placed second in the Republican primary for the 2016 presidential election behind Mr Trump but has said he will run for re-election to the Senate in 2024.
Rick Scott: The Florida senator, 70, has frequently exchanged vitriol with President Biden but says he too will run for re-election to the Senate.