WASHINGTON: (APP) Donald Trump and Hillary Clinton square off Monday for their first presidential debate , a hotly anticipated cage match between a political veteran and an inveterate showman that seems likely to smash US television records.
The 90-minute, prime time debate pits the two White House contenders -- ideological opposites on most issues and separated by just a handful of points in most opinion polls -- in a duel that could help sway the November 8 election.
Tens of millions of Americans are expected to tune in to the debate, held at Hofstra University outside New York City, dissecting the candidates' every word.
Experts say any slip of the tongue, even an errant look or gesture, could affect the opinion of legions of voters.
Some analysts say the bar is higher for the Democrat Clinton, who has decades of experience inside Washington's corridors of power as an ex-secretary of state and former US senator -- but struggles to ignite enthusiasm, even in her own camp.
The Republican Trump's biggest selling point is his status as a Washington outsider, a business mogul and reality television star with a knack for the snappy soundbite -- who few expect to master the nitty gritty of policy.
Clinton has prepared meticulously for the coming clash, carefully studying Trump's primary debate performances, and even consulting psychologists to get a better read on her Republican rival's vulnerabilities, according to one news report.
Complicating her task is that Trump has taken opposite sides of numerous policy positions. He also has a mercurial personality that can vacillate between mellow and combative.
"I do not know which Donald Trump will show up," Clinton, 68, told supporters at a recent fundraiser.
"Maybe he will try to be presidential and try to convey a gravity that he hasn't done before, or will he come in and try to insult and try to score some points."
Going toe-to-toe against Trump means that the wonkish former first lady may have to toss aside her briefing books and don her boxing gloves.
"Her supporters... they want to see her fight this guy," Wendy Schiller, a political scientist at Brown University, told AFP.
"They want to see her take him on directly, and her challenge is to get out of that shell, and really be willing to take on Donald Trump , get under his skin, make him mad," Schiller said.
"That's a winning strategy for her, but it is a challenge for her because that is not her style."
Clinton was forced off the campaign trail for a few days earlier this month while she recovered from pneumonia, ensuring that public concerns about her health -- and her honesty about her health -- will also play a role.
Clinton "will have to convey that she is healthy, that she is vibrant and that she is willing to run the final days of the campaign, in a transparent way that she has not up until this point," said Jennifer Lawless, who teaches at American University in Washington, DC.