U.S. election primer: The presidential debates

The first presidential debate of the 2016 U.S. election season kicks off Monday night.

It's a one-on-one matchup between Democratic nominee Hillary Clinton and Republican candidate Donald Trump. The two candidates vying to follow President Barack Obama are close in the polls, which emphasizes the high stakesfor this contest.

Here's what you need to know about the presidential debates.

When and where?

Monday is the first of three debates between Clinton and Trump, and there is one debate between their running mates, Tim Kaine and Mike Pence. Monday'svenue is Hofstra University in Hempstead, N.Y.

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The second debate is on Oct. 9 at Washington University in St. Louis, Mo., and the finale is on Oct. 19, at the University of Nevada in Las Vegas.

The vice-presidential debate is on Oct. 4 at Longwood University in Farmville, Va.

Who are the moderators?

Lester Holt, the anchor of NBC Nightly News, will kick things off Monday. Elaine Quijano, an anchor and correspondent for CBS News will moderate the vice-presidential debate. Martha Raddatz, chief global affairs correspondent and co-anchor of ABC's program This Week, and Anderson Cooperof CNN, will moderate the second presidential debate. Chris Wallace from Fox News got the pick for the final debate in Las Vegas.

There is an understudy. Steve Scully, who works for C-SPAN, is the backup moderator for all of the debates.

What's the format?

Monday's debate will beginat9 p.m. ET and runfor90minuteswith no commercial breaks. It will be divided into six segments of about 15 minutes each.

Holt will ask a question at the start of each segment and each candidate will have two minutes to respond. Then Trump and Clinton will have a few minutes to respond to what the other said. Holt will steer the conversation for the remainder of the segment.

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The second debatewill be in a town-hall format. The candidates will get half of the questions fromthe audience, who will all be uncommitted voters, and half from the moderators. Trump and Clinton will have two minutes to respond to each question and an additional minute for the moderator to facilitate further discussion.

The final debate's format will be the same as the first one.

Whopicksthe questions?

The moderator does. No, the candidates do not know them in advance. They do know, however, the broad topics. Holt announced a week ago that the questions will be related toAmerica's direction,achieving prosperity andsecuring America.

Why areother candidates left out?

They didn't make the cut, according to the Commission on Presidential Debates, which sponsors the debates and sets the criteria.

The rules for 2016 say to get in the debate you have to be on the ballot in a sufficient number of states to have a mathematical chance of winning enough electoral college votes to win the election. Second, you have to get at least 15 per cent support in five different national polls. Which polls? The commission chooses and takes the average.

On Sept. 16, it announced that only Clinton and Trump met the bar. Libertarian presidential candidate Gary Johnson'spolling average was 8.4 per cent and the Green Party's Jill Steinwasat3.2 per cent.

The same criteria will be applied in advance of the second and third debates, so if Johnson and Stein move up in the polls in the coming days, they might have a chance to share the stage and spotlight with Trump and Clinton in October.

The commission says the purpose of the criteria is to identify the candidates who have a "realistic chance" of being elected president.

What do Johnson and Steinsay?

Plenty. Johnson is a former governor of New Mexico and was also the Libertarian candidate in 2012, but he's not a household name. He has said he needs to be in the debate so Americans can learn who he is, what he stands for, and in an election where the two leading candidates are deeply unpopular, that there is an alternative choice.

It would be "game over" for his chance of winning the election if he's not in the debate, he said in an interview.

Johnson says the commission was created by Republicans and Democrats who don't want third-party intrusions into their televised debates for all voters to see, and this is a classic example of a rigged system. He has his sights set on qualifying for the second debate.

Stein also reacted by slamming the commission as a biased group that is upholding "two-party tyranny." She plans on showing up Monday anyway and is urging supporters to join her at the gates of the university to demonstrate.

How many Americans watch?

Until 2012, the record for TV viewership was held by the 1980 debate between Jimmy Carter and Ronald Reagan. It was surpassed thenby the Barack Obamaand Mitt Romney debate, which attracted46.2 million households, according to Nielsen, a company that measures TV viewership.

This year, given how nasty the campaign has been between Clinton and Trump, more Americans might be interested in watching than usual. The major networks will all air the debates on the good old fashioned television, but they will also livestream it on their websites. Twitter and Facebook are also getting in on the action and offering livestreams.

What about Monday Night Football?

That's right, usually on Mondays,millions of Americans gatheraround the tube to watch football, not political debates. Soon after theNew Orleans Saints and Atlanta Falcons take the field, Clinton and Trump will take the stage, and football-loving Americans will have to make a choice.

The second debate is on a Sunday, another big footballviewing day in the U.S. Trump complained about the scheduling.