• by Wendy Davis  @wendyndavis, March 23, 2018

The Senate Commerce Committee will summon Facebook CEO Mark Zuckerberg to testify about revelations that Cambridge Analytica harvested data from 50 million users of the social networking service.

"On a bipartisan basis, we believe Mr. Zuckerberg’s testimony is necessary to gain a better understanding of how the company plans to restore lost trust, safeguard users’ data, and end a troubling series of belated responses to serious problems," Senators John Thune (R-South Dakota) and Bill Nelson (D-Florida) stated Friday.

Their statement comes one day after leaders of the House Commerce Committee also said they plan to ask Zuckerberg to testify.

Lawmakers are responding to reports that President Trump's consultancy, Cambridge Analytica, obtained personal data of 50 million Facebook users. Cambridge Analytica reportedly obtained the data from Global Science Research's Alexsandr Kogan, who collected the information in 2014 via his personality-quiz app "thisisyourdigitallife." That app was downloaded by 270,000 Facebook users, but Kogan was able to gather information about millions of those users' friends.

In April of 2015, Facebook stopped allowing developers to access data about users' friends. But in 2014, when Kogan's app scraped the data, Facebook allowed developers to glean information about users' friends, subject to their privacy settings. Facebook's terms of service prohibited developers from sharing that information.

Facebook learned in 2015 that Cambridge Analytica had obtained the data, and asked the consultancy to destroy it. The social networking service says it believed at the time that Cambridge Analytica did so.

Cambridge Analytica CEO Alexander Nix, who was suspended from the company this week, boasted to an undercover reporter that the company's extensive ad targeting helped Trump win the presidency. Cambridge Analytica denies using the Facebook data on Trump's behalf.

But the company may have used the data on behalf of other politicians. A political action committee founded by John Bolton -- newly tapped White House national security adviser -- hired Cambridge Analytica to use psychographic modeling on behalf of candidates in 2014, The New York Times reports. Cambridge Analytica reportedly used Facebook data in that initiative.

Cambridge Analyitca said Friday that it believed the data was "obtained in line with Facebook’s terms of service and data protection laws."

The company also says it will be audited, to verify that it no longer has the Facebook data.