(Reuters) -Nikki Haley is the only Republican candidate left in the battle against Donald Trump for the party's nomination to take on Democratic President Joe Biden in November's U.S. presidential election.
Here are the Republican Party's two remaining candidates:
DONALD TRUMP
The Republican frontrunner with 64% support, according to Reuters/Ipsos polling, Trump has leveraged his unprecedented legal challenges, which include 91 indictments in four criminal cases, to boost his popularity among his base and raise money.
The former president scored victories in nominating contests in Iowa, New Hampshire and Nevada and hopes to replace Republican National Committee leadership with allies ahead of his party's July convention.
Trump, 77, has said the criminal charges he faces are part of a political witch hunt designed to keep him from winning, a claim the U.S. Justice Department has denied.
Some of his legal challenges have reached the Supreme Court, including his eligibility for the ballot following the Jan. 6 attack on the U.S. Capitol as well as his claim of presidential immunity.
If elected to another four-year term, Trump has vowed revenge and adopted increasingly provocative language, saying he would not be a dictator except "on day one" and promising to overhaul the federal civil service.
He sparked criticism from Western leaders after saying the U.S. would not defend NATO members that failed to spend enough on defense and would encourage Russia to attack them. He pressed congressional Republicans to stall a military aid package for Ukraine.
Trump has made immigration his top domestic campaign issue, declaring he would impose mass deportations, end birthright citizenship and expand a travel ban on people from certain countries.
He has repeated calls to impose the death penalty on drug dealers, said other alleged criminals could be shot dead, and suggested he would unilaterally send federal troops into Democratic-run localities.
On abortion, Trump has taken credit for the U.S. Supreme Court ruling overturning Roe v. Wade, but he has criticized some Republican-led states' six-week abortion bans.
He has promised other sweeping changes, including eliminating Obamacare health insurance and imposing 10% across-the-board tariffs. On energy, Trump would seek to undo much of the Biden administration’s work to fight climate change and launch new efforts to expand fossil fuel production.
NIKKI HALEY
A former South Carolina governor and Trump's ambassador to the United Nations, Haley, 52, has emphasized her relative youth compared to Biden, 81, and Trump, as well as her background as the daughter of Indian immigrants.
She has gained a reputation in the Republican Party as a solid conservative who could credibly tackle issues of gender and race, but she trails Trump in the polls, drawing 19% support among Republicans in the Reuters/Ipsos survey.
Trump has increasingly targeted her, lobbing racist attacks on her ethnicity and amplifying false claims about her eligibility for the White House despite her being born in South Carolina.
Haley, in turn, has sharpened her attacks on Trump, calling him "diminished" and "unhinged" and arguing he is too chaotic and divisive to be effective.
Haley has largely avoided talking about Trump's legal cases, but has said she would pardon him if he is convicted on federal criminal charges.
She has suggested she will stay in the race past the Feb. 24 primary in her home state.
Haley has pitched herself as a stalwart defender of American interests abroad, citing Trump's praise of dictators and slamming his support for Russian President Vladimir Putin after Russian opposition leader Alexei Navalny's death.
She also backs changes to Social Security and Medicare safety net programs for seniors and vowed to dramatically reduce the size of the U.S. government by shifting some federal programs to states. She has said she personally opposes abortion and has sought national consensus on the issue.
Haley has also called for making some tax cuts permanent and eliminating the federal gas tax. On energy, she supports opening up the Keystone and other pipelines, speeding up permitting and increasing liquified natural gas (LNG) exports.