Your Questions About Presidential Debates, Answered

Vice President Kamala Harris and former President Donald Trump will face off in a debate on Sept. 10—the second presidential debate of the 2024 election cycle, but the first with the new Democratic nominee at the top of the ticket.

The debate will be hosted at 9 p.m. ET by ABC News and will run for 90 minutes. The format will be similar to the CNN debate in June between President Joe Biden and Trump, before Biden announced he was ending his re-election campaign and endorsed Harris for the Democratic nomination.

In light of the upcoming debate, TIME has answered your questions about presidential debates—from when they first started to who is eligible to participate.

When was the first presidential debate?

While many people consider the first televised debate to be the one between John F. Kennedy and Richard Nixon in 1960, historians have argued that the first televised presidential debate actually happened four years before—although it featured surrogates for the candidates.

Democratic candidate and former Illinois Governor Adlai Stevenson and Republican President Dwight Eisenhower didn’t appear in the debate on Nov. 4, 1956. Instead, former First Lady Eleanor Roosevelt represented the Democrats, while Maine Senator Margaret Chase Smith represented the Republicans.

The debate was broadcasted by CBS on Face the Nation (it was the first time a woman appeared on that program, according to the U.S. Senate’s website). The debate took place just two days before the election, and the main topic of the debate was foreign policy.

Read More: These Are the Rules of the ABC Presidential Debate

Who organizes presidential debates?

In 1987, the Commission on Presidential Debates was formed as a private, nonprofit, nonpartisan corporation to “organize, manage, produce, publicize and support debates for the candidates for President of the United States.”

The commission doesn’t endorse or oppose political candidates or parties, and has sponsored general election presidential debates in every election since 1988. Before then, the League of Women Voters organized the presidential debates of 1976, 1980, and 1984.

This year, though, CNN and ABC directly organized the debates, after Biden said that he would not participate in presidential debates sponsored by the commission, according to the Associated Press. Previously, the Republican National Committee had vowed not to work with the commission.

Are presidential debates required by law?

While the Commission on Presidential Debates’ main goal is to ensure that general election debates are held every four years between the leading presidential and vice presidential candidates, the debates aren’t required. After the Kennedy-Nixon debates in 1960, there weren’t any debates in 1964, 1968, and 1972, according to the commission.

How many presidential debates were there in 2020?

During the 2020 election cycle, Biden and Trump participated in two debates. The first took place on Sept. 29, 2020, and was marked by its antagonistic tone, as Trump and Biden repeatedly spoke over each other and attacked the other’s character. Initially, Trump and Biden were supposed to participate in a second debate on Oct. 15, 2020, but the debate was canceled after Trump was diagnosed with COVID-19 and declined to do a virtual debate. The two candidates took the debate stage for a second time on Oct. 22, 2020—what would have been the third debate.

What does it take to qualify for a presidential debate?

To qualify for the Sept. 10 presidential debate, candidates must have met the following requirements announced by ABC:

How many Americans watch presidential debates?

The U.S. presidential debates are some of the most watched televised events in the country, in addition to the Super Bowl. In 2020, more than 73 million people watched at least some of the first Trump-Biden debate, according to Nielsen Media Research, making it the third-largest debate audience ever. 

The most watched event was the first debate between Hillary Clinton and Trump in 2016, which reached 84 million viewers, according to Nielsen Media Research. The 1980 debate between Jimmy Carter and Ronald Reagan was the second most watched debate, with 80.6 million viewers.

Ratings for the presidential debates have fluctuated over the years, according to data from Nielsen Media Research. The four debates in 1960 all had ratings of about 60.0—that means that about six-in-10 households with TVs were tuned to the debates. But in 1976, when the debates continued, their ratings were lower, and they continued trending lower over the next couple decades. After the third debate between Al Gore and George W. Bush in 2000, though, debate ratings have mostly trended upward—the first Trump-Biden debate in 2020 had a rating of 40.2.

More than 51 million people tuned into the CNN debate between Biden and Trump in June, according to Nielsen Media Research. The fallout from that debate marked a major shift in the 2024 election cycle, as Biden dropped out of the race in the wake of his poor performance after politicians and prominent Democratic donors called on him to step aside.