Moderator Elaine Quijano failed to fact-check Republican Indiana Gov. Mike Pence during the vice presidential debate, enabling him to freely lie about positions advocated by his running mate, Donald Trump, with no repercussions or corrections, highlighting the necessity of moderator fact checks.

At the debate table, Democratic candidate Sen. Tim Kaine (D-VA) challenged Pence to answer for a number of Trump’s previously criticized policy positions and statements, including a proposal to create a “deportation task force,” his praise for Vladimir Putin, his advocacy for a ban on Muslim immigrants, and his claim that there “has to be some form of punishment” for women who seek abortions. Pence responded by whitewashing Trump’s past and denying that Trump made the remarks he did. Media, in turn, criticized Pence for defending Trump “by conjuring a candidate who does not exist.”

For her part, Quijano failed her obligation to clarify the facts to viewers and let audiences know that Pence was lying about Trump’s expressed positions. Quijano could have clarified that Kaine’s questions to Pence contained truth, but instead she allowed Pence to disavow Kaine’s questions as “insults” and deny the validity of his claims.

Quijano also missed several opportunities to correct Pence’s lies that Democratic presidential nominee Hillary Clinton supports aborting full-term babies (she doesn’t), is responsible for withdrawing troops from Iraq in 2011 (she’s not), and wants to turn the Affordable Care Act into a single-payer system (not true).

Journalists have repeatedly stressed the “obligation” moderators have to their audiences to fact-check candidates during debates, arguing that journalists selected to moderate a debate must distinguish reality from fiction by “asking tough follow-up questions” and adding “clarity if needed.” Research suggests that people who encounter fact-checked news feel more confident that they know what is fact than those contemplating unchecked “he-said-she-said” information.

Last month, Lester Holt’s moderation of the September 26 presidential debate demonstrated the need for moderators to prove real-time fact checks of blatantly false information, and Matt Lauer’s moderation of the NBC News Commander-in-Chief Forum demonstrated the risks of having moderators who won’t.

Pence’s freedom to deceive and smear during the vice presidential debate reminds us of the duty moderators have to hold political candidates accountable to the public. Quijano’s failure to push back on Pence’s falsehoods demonstrates the consequences of moderating debates unchecked.

Fox News host Chris Wallace, who will moderate the final debate this fall, has already declared that he does not intend to ensure candidates are honest, claiming it is not his job “to be a truth squad.” Media Matters founder David Brock has penned a letter to the Commission on Presidential Debates asking members to reconsider Wallace's selection.