Long-recognized problems of online abuse and impersonation are being taken more seriously now. U.S. senators last week grilled three executives from California-based technology giants – Facebook, Twitter and Google – about foreign propaganda aimed at U.S. voters during the 2016 presidential campaign. "Social media have been spreading poison," The Economist magazine says in a cover article this week. Senate Intelligence Committee members are looking into ads and fake news posts – particularly from Russia – that meddle with democracy. Efforts included posts pretending to be from Americans and a barrage of false information intended to spur protests or cause topics to trend – tactics that worked. "Social media tools . . . magnify propaganda and fake news on a scale that was unimaginable back in the days of the Berlin Wall," Sen. Mark Warner, D-Va., said during two days of hearings. "Today's tools seem almost purpose-built for Russian disinformation techniques."

Political meddling had a vast scope, the witnesses testified: Russian agents spread inflammatory posts that reached 126 million Facebook users and put over 1,100 videos on Google's YouTube service. They’re also linked to more than 1.4 million election-related tweets just from September to November 2016. Those totals are far higher than what the companies had revealed earlier, and some lawmakers accuse the companies of not taking seriously what Congress considers a kind of cyberwarfare.

Facebook vows "to prevent it from happening again," the company's top lawyer told senators. Twitter recently banned two Kremlin news organizations from advertising on its site. And Google said it suspended 18 channels that were "likely associated" with Russian agents posting political videos totaling 43 hours of content from 2015 through the summer of 2017.

In Congress, one response is a bill from Democratic Sens. Amy Klobuchar of Minnesota and Mark Warner of Virginia, who want to require internet companies to identify the sponsors of political ads. Online ads should face the same kind of regulatory scrutiny as do sponsored messages on TV radio and in print, the senators say. "What we have to ask ourselves is: Do we want to be suckered again? . . . What the disclosure will do is police everyone that puts out political ads, and give a fighting chance for journalists and campaigns to see what’s going on," says Klobuchar.

Senator says: "You've created these platforms, and now they are being misused. And you have to be the ones to do something about it, or we will." – Diane Feinstein, D-Calif.

Executive says: "Facebook is committed to preventing that sort of behavior from occurring again on our platform." -- Colin Stretch, general counsel

Journalist writes: "Without this information, citizens cannot take stock of how they might have been influenced." – Sarah Kendzior, St. Louis reporter in NBC News commentary