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Representatives for Facebook, Twitter and Google are facing the Senate on Tuesday afternoon, as lawmakers grill the general counsels of the three social media firms to ascertain what role Russian interference played in last year's presidential election.

Ahead of Tuesday's hearing, for instance, Facebook revealed that an estimated 126 million Americans saw Russian-backed content on the social media platform during the 2016 campaign.

NBC News spoke with legal and tech experts to find out what legislators should be asking Facebook, Twitter and Google about Russian interference in the election and what to do about it.

Joel Winston, a privacy law expert and former New Jersey deputy state attorney general; Scott Galloway, a professor of marketing at the NYU Stern School of Business; Shelly Palmer, the CEO of the advertising tech consultancy The Palmer Group; and Jonathan Albright, research director of the Tow Center for Digital Journalism, shared their thoughts on top questions lawmakers should ask Facebook, Twitter and Google.

Related: Tech Titans Grilled By Senate About Russian Propaganda

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Below are edited and condensed versions of their questions.

1. All the major media companies and newspapers can commit to not being weaponized by Russia: Can your organizations make that promise? Why should you be held to a different standard than any other media company? Will you commit to providing whatever resources are necessary — even if it reduces your profitability — to ensure this will never happen again?

2. If you create original content and serve news to more than 50 percent of Americans and run ads against it, doesn't your media company have a responsibility to put safeguards in place to protect our democracy? Facebook has claimed it is not a media company because it hires more engineers than reporters. Well, the NBA has more tech employees than athletes. Does this mean they’re a tech company?

3. You've testified that foreign entities sought to influence the election through the use of your platform. How many users on your platform came into contact with posts, ads or content that originated from foreign entities? What steps has your company taken to notify such users that they were subjected to attempted influence by foreign entities?

Related: Facebook Says Russian-Backed Election Content Reached 126 Million Americans

4. Google search results are being manipulated and we’re still seeing content from bad actors being served prominently. Why? How is auto-complete being used when people are trying to verify a claim?

5. What information can you share on how Russians used not just Facebook, but Instagram and Facebook Messenger? Why hasn't much been shared about these powerful platforms?

6. Was personally identifiable data of any of your customers used in any way contrary to your terms of service? If yes, by whom and how so? And what steps did your company take in response?

7. Were your advertising tools or technologies used to conduct “voter discouragement” activities? If yes, by whom and how?

8. What specific roles did your employees play in the campaigns' day-to-day social media messaging and advertising activities?

9. What internal investigations have your companies conducted regarding campaign efforts at “voter suppression” during the campaign?

10. Was personally identifiable data of any of your customers used in any way to target voter suppression, voter discouragement, fake news or offline activities? What custom audiences data did the Trump campaign use to target voters on your platform? What was the source of this data and how were the data targets integrated into your platform?