Tuesday Risk: A Cybersurprise

It wouldn’t take much to disrupt Tuesday’s vote in a few important swing districts, and that’s what the United States government — and many private security experts — are worried about.

The Department of Homeland Security says it will be deploying small teams of cyberexperts to important states — presumably those that are most vulnerable, or have close races — just before the election. But it is not hard to imagine different scenarios that could cause disruption, or just create the illusion of disruption.

A last-minute attack on county or state voter-registration systems, just to knock them off-line, would create an uproar from voters who might show up at the polls and find they could not vote. A strike at power grids, turning out the lights at polling places, or just disrupting transportation systems could suppress turnout and lead to charges of manipulation.

Mr. Rosenbach’s group simulated such events in a series of scenarios with election officials, piling one attack upon another in an effort to get them to think ahead about how they would respond, all part of an election “playbook” that the Defending Digital Democracy program has given to campaigns and officials.

And then there is another fear: Come Wednesday, if there are still races that are too close to call, just a rumor campaign about possible election manipulation might be enough to cast doubt about the integrity of the results. And in the end, that’s what election disruption is all about — undermining the citizens’ confidence that their vote counts.

The Missing Evidence

In 2016, the evidence of the extent of Russian operations on social media did not become clear until months after the election was over — and then, time and again, Facebook had to admit it missed all the warning signs. Mark Zuckerberg, a company founder, moved from arguing that to think fake news and divisive posts “influence the election in any way is a pretty crazy idea” to ordering the hiring of thousands of Facebook monitors to make sure it never happened again.

But there are no guarantees. Months after the midterms are over, evidence of covert internet action that is currently going unnoticed may well surface. As the Russians and others embrace artificial intelligence techniques, and get better at targeting messages, they may well find ways to route around the phalanx of new social-media police. Ms. Green says that is unavoidable.

“It’s still retroactive,” she said of monitoring social media. “We haven’t figure out how to do this in real time.”