The build-up to the 2020 US presidential elections between Joe Biden and Donald Trump saw disinformation spreading rapidly. Trump-appointee Chris Krebs, the director of the Cybersecurity and Infrastructure Security Agency (CISA), had spent years enhancing election security while developing an apolitical reputation. But now Trump was questioning the election’s validity, and his close allies were sharing a false story about a supercomputer flipping votes. How could Krebs respond in a way that preserved widespread trust in the elections?