Clearly, the presidential debate between Joe Biden and Donald Trump in June was one of the most consequential in presidential history. It directly resulted in Biden’s departure from the race and the ascendance of Kamala Harris to the Democratic nomination. 

But it had another notable feature: a noticeable lack of fact-checking. 

While Biden meandered and wandered, saying things that either didn’t make sense or were hard to follow, Trump turned to his very long regular playlist of falsehoods about the economy, abortion, immigration and election fraud. CNN’s Jake Tapper and Dana Bash didn’t fact-check either one, giving a simple “thank you” to each answer and moving on to the next question. It was a purposeful laying back and letting the candidates say whatever they wanted.

You can argue, and CNN did, that a passive approach keeps the moderators out of the story and allows the candidates to reveal themselves. But it’s also an approach criticized — rightfully so — for leaving the voting public in the dark. In the high-stakes race for the presidency, many voters are just tuning in and not well-versed in current political messaging. They won’t necessarily know what’s true and what’s false without getting at least a few cues from journalist moderators. 

Trump and the Democrats’ new nominee, Vice President Kamala Harris, are facing off Tuesday night in a debate moderated by ABC’s David Muir and Linsey Davis. While the supporters and detractors of Trump and Harris tend to dominate social media, many less partisan Americans will tune in looking for basic information before casting a vote. Debate moderators who don’t contradict the candidates in their lies and spin are doing these voters a disservice. 

One of the arguments CNN made is that live fact-checking is hard and would derail the pace of the debates. Others argue that fact-checking is ultimately subjective, or simply too time consuming. I’m arguing against all of those points. Prepared journalists can be effective and even artful in confronting debate lies. There are important techniques that don’t shout out, “Hey, I’m fact-checking you right now!” But they are, indeed, fact-checking, and crucially helpful to voters seeking information.

Here are five techniques debate moderators should use when they want to hold the candidates accountable through fact-checking.

Insist on direct answers 

Debate moderators absolutely must do their homework and understand the substance of their questions so they can spot lies and make a contradictory case in real time. Very few are as good at this as ABC’s Martha Raddatz, a longtime expert in foreign policy. 

In a 2015 presidential primary debate between Hillary Clinton and Bernie Sanders, Raddatz was widely praised for her tough questioning on foreign policy. Raddatz asked Clinton what the Obama administration’s responsibility was after a 2011 intervention in Libya fell apart; Clinton gave a lengthy answer that basically said the administration had done everything it reasonably could. 

Raddatz was ready to challenge that: “On the security side, we offered only a modest training effort and a very limited arms buy-back program. Let me ask you the question again. How much responsibility do you bear for the chaos that followed those elections?” And even after that, Raddatz came back one more time with, “But were mistakes made?”

Help the candidates fact-check each other

Candidates are widely expected to fact-check each other in debates, and the best moderators facilitate and encourage this dynamic. One of the chief criticisms of Biden from his own party after the June debate is that he wasn’t able to do this. But in 2020, Biden was effective, especially in the final debate of the 2020 cycle, ably moderated by NBC’s Kristen Welker.

Welker took a low-key approach to fact-checking, but her key strength was that she kept turning to each candidate for quick responses to their opponent. She encouraged a rat-a-tat-tat of responses between Biden and Trump on the pandemic, Russian election interference, the economy, the business of Biden’s son Hunter. She didn’t step on or interrupt their fact-checking of each other. And her no-nonsense attitude and verbal cues — clearly stating she intended to keep the candidates within time limits — had the effect of encouraging a robust exchange.

Comment for the record and move on

In that 2020 debate, Welker also chose two spots to interject her own fact-checking of Trump with brief comments that didn’t challenge him to answer, but simply set the record straight.

After Trump said that most people easily recover from COVID, especially young people, as if catching COVID were no big deal, Welker said, “And, of course, the CDC has said young people can get sick with COVID-19 and can pass it.” It was quick and to the point. 

On the issue of immigration and children being separated from parents at the border, Trump said, “They are so well taken care of. They’re in facilities that were so clean.” Welker simply responded, “But some of them haven’t been reunited with their families” — a well-timed comment the got to the heart of the matter. 

These corrections are particularly laudable because Welker chose important topics to correct: a serious issue of public health and a major humanitarian issue of widespread concern.

Fact-check important topics, not trivial ones

Moderators shouldn’t waste time on fact checks that aren’t important. An example of what not to do came when CNN’s Candy Crowley fact-checked Mitt Romeny in a 2012 debate with Barack Obama. The incident has been debated for years whether Crowley got it right or not. The problem here was that, while the fact check was about an important topic, the fact check itself drilled down on a process detail that wasn’t so important. Let’s review.

The topic again was Libya, and Romney’s attack line was this: “It took the president 14 days before he called the attack in Benghazi an act of terror.”

Crowley contradicted Romney, saying “(Obama) did in fact, sir. … (He did) call it an act of terrorism.” Obama seized the moment, saying, “Can you say that a little louder, Candy?” 

Crowley then hedged: “He did call it an act of terror. It did as well take — it did as well take two weeks or so for the whole idea of there being a riot out there about this tape to come out. You (Romney) are correct about that.” The tape, for those who don’t remember, was an American-made video mocking Islam, and for a brief time it was thought to have provoked a spontaneous riot at the U.S. mission in Benghazi. As evidence developed, it was clear the attack was pre-planned.

This exchange got a huge amount of attention about whether Crowley was successful in her fact check or not, and unfortunately it all hinged on a parsing of what words Obama used at a Rose Garden press conference. (Read longer fact checks here and here.) Was Obama calling Benghazi an act of terror, or was he just speaking about violent acts in general and placing Benghazi in that context? This hardly seemed the most important part of the Benghazi attack. 

Lost in the fray about what Obama said when was the actual policy response to Libya, or ways America could have saved lives or protected its foreign policy interests better. 

Cover a few topics well instead of many poorly

Most debates try to cover too many topics. When a moderator starts a debate announcing they intend to cover all the important issues on voters’ minds, I heave a sigh of resignation. It means the debate is likely to be superficial, argumentative and even boring. 

No debate can be all things to all voters, and journalists make a mistake if they think that more topics are better. Most voters are tuning in to get a sense of the person who is the candidate: How well do they articulate their positions? Do they seem strong or weak in doing so? What is the sense of their character or personality? The facts do matter, very much so, but they are not the only things that matter.

Setting up a debate to be substantive and thoughtful is more important than moving through the topics as quickly as possible. The Poynter Institute’s recent OnPoynt report on news trends noted that ethical journalism and high-quality coverage are the best ways to build trust and stand out in a news marketplace oversaturated with content.

Making political debates more substantial through public-interest fact-checking that is smart and tailored to the TV format would help the largest national news organizations truly distinguish themselves.