US presidential candidates Joe Biden and Donald Trump face off on Thursday in the first of two debates ahead of November's razor-close election, with both aiming to use the 90-minute duel to win over crucial undecided voters.
The contest is a rematch of 2020, when the world was in the depths of the Covid-19 pandemic. Four years later, the US is roiled by bitter fights over immigration policy, abortion rights, the pain of inflation, and Trump's myriad of criminal cases, including his attempt to overturn Biden's win in the last election.
Foreign policy could feature prominently in the clash hosted by broadcaster CNN in the southern city of Atlanta, given the eight-month-old Israel-Hamas war and the tense relations with China over trade and Taiwan.
Many in Europe are alarmed by the prospect of Trump returning to the White House, not least because of doubts the US would continue to support Ukraine's fight against Russia's invasion and his promise to fundamentally rewrite Washington's 75-year relationship with NATO.
This will be the third time Biden and Trump have met on a debate stage. Hanging over the showdown are worries about their age, temperament and mental fitness. Biden, the current Democratic president, is 81. Trump, his Republican predecessor, is 78. They are the two oldest candidates to ever seek the US presidency.
Biden has been out of the public eye prepping for the debate with close aides at Camp David, a mountain retreat outside of Washington. Trump, on the other hand, downplayed the importance of preparation, saying this week he had been training for the debate his "whole life."
Polls show most Americans long ago made up their minds on who they will vote for, meaning the debate is unlikely to dramatically shift the neck-and-neck race.
Yet recent US elections have been won and lost thanks to a relatively small number of voters in a handful of states that can swing either Democratic or Republican. Biden and Trump need to gain the support of political independents and those who have been tuned out up until the wall-to-wall news coverage generated by Thursday's debate.
The two take the stage at 9 pm (0100 GMT Friday). In contrast to previous debates, there will be no studio audience and the candidates' microphones will be muted until it is their turn to speak.
A second presidential debate is scheduled for September 10, after Biden and Trump formally accept their parties' nominations at conventions in July and August.
It is still unclear whether and when there will be a TV debate between the candidates for vice president. Biden is once again entering the race with Kamala Harris at his side; Trump has not yet named a running mate.
