The narrative of the 2024 US election campaign has already been torn apart by one TV debate. Now another one looms as Kamala Harris prepares to take on Donald Trump for the first time on Tuesday night.
Until President Joe Biden, 81, and the 78-year-old Trump met on stage in late June, the storyline appeared set: two unpopular and elderly candidates would go head to head on November 5 for a matchup that few voters appeared to relish.
That all changed when Biden put in a shambolic performance, forcing him to bow out and to anoint Vice President Harris, 59, in his place.
Now Trump is the old man of the race, and facing mounting questions over his own mental acuity with his campaign speeches veering all over the rhetorical map.
She has revitalised Democratic hopes. Another narrative-shredding moment when Trump survived an assassination attempt in Pennsylvania appears long ago now.
The ABC debate in Philadelphia, which airs from 2am UK time on Wednesday, will mark the first time that Ms Harris and Trump will meet one on one.
It could well be the only debate before November, giving it an outsized importance with polls showing the White House race is tightening again after a convention bounce for the Democrats.
There will be no studio audience, and a candidate’s microphone will be muted when she or he is not speaking, potentially denying viewers the chance to hear Trump’s off-camera antics.
The hopes of millions are invested in the biracial Harris to make history as the first woman president, and to stop a second-term Trump from delivering on his increasingly doom-laden threats of retribution against his political enemies.
Ms Harris, a former prosecutor and attorney-general in California, says she is ready to counter the Republican’s well-worn tendency to interrupt, to bloviate and to outright lie.
"There's no floor for him in terms of how low he will go," she told a radio host as she hunkered down in Pennsylvania for nearly a week of debate preparation.
Trump has stuck to a schedule of public rallies and events in front of his adoring Maga fans, amplifying a narrative of conspiracy theories on the baseless grounds that he was cheated of victory by Biden in 2020.
The woman he defeated in 2016, Hillary Clinton, had to deal with a barrage of debate insults from Trump that smacked of misogyny to many observers.
"President Trump is going to be himself," senior adviser Jason Miller told reporters ahead of the Philadelphia showdown, denying he intends to moderate his tone facing another woman in Harris.
The Republican’s campaign says she tends to devolve into a meaningless "word salad", and is also vulnerable for her policy U-turns down the years. Trump said last week that his debate strategy was to "let her talk".
But his language on social media and at rallies has been getting even more agitated, as he threatens “long term prison sentences so that this Depravity of Justice [in 2020] does not happen again”.
Republican strategists are warning Trump to put his grievances aside against Harris, and focus on policy.
"If she performs great, it's going to be a nice surprise for the Democrats and they'll rejoice," said Ari Fleischer, former press secretary to President George W. Bush.
"If she flops, like Joe Biden did, it could break this race wide open. So there's more riding on it," he said.
