WASHINGTON - Barack Obama and Mitt Romney face off Wednesday in their first presidential debate, a hotly anticipated showdown that will give voters a closer look not just at their disparate ideas for America's future but also how they handle the pressure-cooker of a high-profile mega-event.
While debates haven't historically altered the course of a presidential campaign, millions of Americans tune in for them — as many as 60 million are estimated to be preparing to watch the first of three presidential sparring matches, this one on domestic policy at the University of Denver.
First lady Michelle Obama said in an interview earlier this week that the showdowns are nail-biters.
"I get so nervous at these debates ... I'm like one of those parents watching their kid on the balance beam," she told CNN. "You're just ... just standing there just trying not to have any expression at all."
She'll be in Denver to watch the debate, which happens to be taking place on the president's 20th wedding anniversary.
Ann Romney, meantime, said she'll revert back to her usual role — that of the "Mitt Stabilizer," as her children have dubbed her.
"I feel like that's my role for Mitt, especially when he's going through such a difficult time. I'm there for him. We're there for each other emotionally all the time. In the last 20 debates that we did in the primary, I felt that was my most important role."
There have been nine sets of presidential debates since the first televised event in 1960 between Richard Nixon and John F. Kennedy. But only twice has the politician trailing in the race come from behind, post-debate, to win the election.
Nixon, recovering from knee surgery, perspired so profusely that it was thought to have cost him the election as, post-debate, Kennedy squeaked past him in the polls. In 2000, George W. Bush overtook Al Gore following their debates.
Nonetheless the Denver debate is considered particularly important for Romney. While he's narrowed Obama's lead in national polls in recent days, Romney's still trailing the president in several critical swing states that will decide the outcome of the Nov. 6 vote.
The showdown is considered his last high-profile chance to turn his struggling campaign around — and to fight back against perceptions, skilfully put forward by the Obama campaign, that he's an unfeeling rich man only looking out for his own.
The president's challenge will be to deliver short, pithy answers; he tends to ramble on. Obama also visibly bristles when he doesn't like questions posed to him.
That's a danger spot for the president given he'll be on the defensive about the economy, in particular, and possibly about his administration's handling of the anti-American violence in Libya that resulted in the death of the U.S. ambassador to the North African country last month.
Both campaigns have been working hard to build up expectations for their rival, reasoning that the higher the hopes, the more scathing the criticism if they fail to do well.
David Axelrod, Obama's senior adviser, said this week that debates "generally favour challengers" and praised Romney's debating skills.
Romney's campaign, meanwhile, waxed positively poetic about Obama.
"President Obama is a uniquely gifted speaker and is widely regarded as one of the most talented political communicators in modern history," top Romney aide Beth Myers said.