Soon, the ballots will be cast, the polls will close and a campaign marked by assassination attempts, animosity and anxiety will come to an end. But for U.S. adversaries, the work to meddle with American democracy may be entering its most critical phase.

Despite all the attention on efforts to spread disinformation in the months before the Nov. 5 election, the hours and days immediately after voting ends could offer foreign adversaries like Russia, Iran and China or domestic extremist groups the best chance to mess with America’s decision.

That’s when Americans will go online to see the latest results or share their opinions as the votes are tabulated. And that’s when a fuzzy photo or AI-generated video of supposed vote tampering could do its most damage, potentially transforming online outrage into real-world action before authorities have time to investigate the facts.

It’s a threat taken seriously by intelligence analysts, elected officials and tech executives, who say that while there’s already been a steady buildup of disinformation and influence operations, the worst may be yet to come.