FACTBOX-When is the third Republican US presidential debate and who are the candidates?

While DeSantis leads Haley nationally, Haley leads the Florida governor in New Hampshire and South Carolina, two crucial states in the Republican nominating process. A strong debate by either will help them make the case to voters and donors that they have a more plausible shot at closing the gap with Trump.

Republican presidential contenders are scheduled to face off in a third primary debate on Wednesday. Here are some facts about the forum:

WHERE IS IT? The third debate will take place in Miami. NBC News will host the event at the Adrienne Arsht Center for the Performing Arts of Miami-Dade County and air it from 8 p.m. to 10 p.m. ET (0100 to 0300 GMT). Florida is the home of former President Donald Trump and Florida Governor Ron DeSantis, who are running first and second in national opinion polls, respectively.

Florida was until recently a battleground between Republicans and Democrats, but the state now leans conservative. The state hosts a Republican primary contest in March, which has played a crucial role in previous primary elections, though it is considerably less important than contests in Iowa, New Hampshire and South Carolina, which are slated for January and February. WHO WILL BE THERE?

DeSantis, former U.S. Ambassador to the United Nations Nikki Haley, tech entrepreneur Vivek Ramaswamy and former New Jersey Governor Chris Christie appear to have met the requirements to be on the stage. South Carolina Senator Tim Scott's campaign has also said he will be there. North Dakota Governor Doug Burgum and former Arkansas Governor Asa Hutchinson appear not to have made the cut. To qualify for the debate, candidates need to have received at least 4% in two national polls since Sept. 1 or 4% in one national poll as well as 4% in a poll in at least two "early states." Those early states are Iowa, New Hampshire, Nevada and South Carolina, all of which are among the first to hold nominating contests. Candidates are also required to have at least 70,000 unique donors, including at least 200 donors from 20 or more states or territories. They also must sign a pledge which requires participants to support the eventual Republican nominee.

WHAT ABOUT TRUMP? Seeking to bolster support among the Hispanic community in Florida, Trump will hold a rally in Hialeah, a Cuban-American stronghold, starting at 7 p.m. ET. He has repeatedly said he does not believe it makes sense to open himself up to attacks from opponents on the debate stage given his sizeable polling lead. He is up nearly 40% over his nearest challenger, according to the

latest Reuters/Ipsos poll .

WILL THE DEBATE MATTER? The first two debates did nothing to dent Trump's sizeable lead in opinion polls. At the same time, DeSantis and Haley are locked in a fierce competition for second place. While DeSantis leads Haley nationally, Haley leads the Florida governor in New Hampshire and South Carolina, two crucial states in the Republican nominating process.

A strong debate by either will help them make the case to voters and donors that they have a more plausible shot at closing the gap with Trump. Both, however, are far behind Trump in national polls.