Earlier this year, Hanan Melcer, the chairman of Israel’s Central Elections Committee and a veteran justice on the Supreme Court, summoned representatives from major U.S. social-media and technology companies for talks about the role he expected them to play in curbing online deception during the country’s election, which took place on Tuesday. Facebook and Google sent representatives to meet with Melcer in person. Twitter executives, who weren’t in the country, arranged for a conference call. “You say you’ve learned from 2016,” Melcer told them, according to a government official who was present. “Prove it!” When Melcer, two years ago, assumed his role overseeing the election, he expected that covert influence campaigns by foreign adversaries, similar to Russia’s alleged interference during the 2016 U.S. Presidential race, could be his biggest challenge. But, as Melcer and his colleagues looked more closely into the issues they could face, they realized that the problem was broader than foreign interference. Russia’s campaign in the United States demonstrated that fake personas on social media could influence events. In Israel and elsewhere, political parties and their allies realized that they could use similar techniques to spread anonymous messages on the Internet and on social media to promote their candidates and undermine their rivals. The use of fake online personas has a long history in Israel. In the mid-two-thousands, an Israeli company called Terrogence used them to infiltrate suspected jihadi chat rooms. Later, Terrogence experimented with covertly influencing the jihadis they targeted. More recently, companies in Israel and elsewhere started using fake personas to spread messages on behalf of political parties and their allies.