With the highly anticipated first U.S. presidential debate set for Monday night, veteran journalist Jim Lehrer, a seasoned moderator of such contests, is just as happy to sit this one out.

"Oh no, heavens no," he says, when asked if he regrets not participating in the long-awaited political dust-up between Democrat Hillary Clinton and Republican Donald Trump.

But, then, in mid-sentence, he reconsiders.

"Having done as many as I have done — for the most part being exhilarated by the experience — it's hard not to say 'Well, you know I could do this, it might be really interesting.' But 60 to 70 per cent of me — I'm just delighted I don't have to do it."

Instead, the honours will fall to NBC News anchor Lester Holt, who will host the first debate at Hofstra University in Hempstead; N.Y., CNN's Anderson Cooper and ABC News' Martha Raddatz who will moderate the second contest and Fox News' Chris Wallace, who will preside over the third.

As much as the focus will be on the candidates, attention will be drawn to the performance of the moderator. While this is certainly one of the most prestigious gigs a journalist can snag, it can be one of the most thankless jobs.

"There is no way you can do them without being criticized," said Lehrer, who has moderated 12 presidential debates. "So if you don't want to be criticized, don't be a moderator."

Lehrer has felt the sting from critics, and was slammed by some for losing control of the first debate between President Barack Obama and former Massachusetts governor Mitt Romney. (Michael Reynolds/ Reuters)

Lehrer has felt the sting from critics, and was slammed by some for losing control of the first debate between President Barack Obama and former Massachusetts governor Mitt Romney in 2012. But as Lehrer sees it, most of that criticism came from supporters of Obama, who was widely viewed as having lost that matchup.

"If your candidate does poorly in a debate, you don't blame your candidate. You've got to blame somebody. You don't blame the opponent necessarily, unless you've got some kind of fairness issue. Blame the moderator."

(CBC)

Already the role of the moderator in these debates has come under more intense scrutiny than usual, in part due to the controversial performance of NBC Today show host Matt Lauer at a national security forum in New York this month. Lauer interviewed Trump and Clinton separately, but was slammed for not fact-checking the real-estate mogul.

But Wallace has already served notice, and received some backlash, for declaring he would not be fact-checking because it's not his "job to be a truth squad."

Republican presidential candidate Donald Trump speaks with Today co-anchor Matt Lauer at the NBC Commander-In-Chief Forum. Lauer was criticized for not fact-checking the real-estate mogul. (Evan Vucci/Associated Press)

Lehrer says the candidates should fact-check each other.

Alan Schroeder, a Northeastern University journalism professor and author of Presidential Debates: Risky Business on the Campaign Trail, said a debate is not the ideal forum to begin on-the-spot fact-checking. It could create problems.

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Many Republicans cried foul, for example, when CNN's Candy Crowley seemed to take the side of the president against Romney regarding a fact related to the Benghazi embassy attack.

"There's an example of a moderator trying to do real-time fact-checking and kind of had it backfire on her," Schroeder said. "Not that she was necessarily wrong in what she said, but that it was a really nuanced and complicated thing."

There are others — journalists, political observers, fact-checking websites — who are watching the event and are much better suited for that role, he said.

Not a protagonist

A moderator is not a protagonist in the debate but a facilitator of the dialogue between the candidates, Schroeder said.

"The debate ultimately has to be about the candidates and so, you know, this question of how activist moderators should be in a debate — it really is not an interview."

Lehrer said the role is much more than just keeping time, it's making sure the debate is fair, that the candidates are talking about the same subject and are following the rules of the game.

NBC Nightly News anchor Lester Holt is the moderator for the first debate Monday between Hillary Clinton and Donald Trump. (Jose Luis Villegas/Sacramento Bee/Associated Press)

Debate watchers don't understand that it's not the same job as an interviewer, which is one of the reasons they complain that moderators "didn't follow up on this, didn't challenge this, or, you cut somebody off too soon, or you let somebody go on," he said.

"People watch these through the prism of their own beliefs and through their own partisan viewpoints."

Do homework and listen

Lehrer advises moderators to do their homework and listen. "Discern whether or not the answer you just heard is worth following up on, and if so, how and is it relevant. Is there something you should call up the opponent to challenge?"

Also, moderators should study up on the candidates.

"You want to start as on top of things as you possibly can. It's about content in terms of what they believe, in positions they've taken and what proposals they've made, but it's also about them as individuals."

And if a candidate won't answer a question? There's only so much a moderator can do, Lehrer said. Highlight the fact that the candidate didn't answer, repeat the question, but then decide whether the point has been made.

"Everybody now knows they didn't answer this question. Move on. I don't have to declare it, they didn't answer the question. Forget it. The public can figure that out."