As federal investigators continue to find evidence that Russian nationals interfered in the 2016 U.S. elections, lawmakers have struggled to find ways to combat any repeat efforts in 2018.

One potential solution? Fining social media titans like Facebook and Twitter— where Russians pose as people and groups within the U.S. to promote certain political views and events — whenever they fail to deactivate “bots” on their platforms.

“I think that would be a great idea,” Democratic Sen. Amy Klobuchar of Minnesota said Sunday on NBC’s “Meet The Press.” “But then you need a Congress to act, and there are too many people who are afraid of doing something about this because we know these sites are popular.”

Special counsel Robert S. Mueller has handed down criminal indictments to 13 Russian nationals and three Russian companies for trying to help President Donald Trump win the 2016 election. Those companies and individuals targeted social media users on Facebook and Twitter.

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“There’s an ugly side of this. And someone once said that these systems were set up without alarms, without locks, and big surprise, bad guys are coming in and manipulating people,” Klobuchar said. “The idea of a fine is like when a company dumps toxic waste, makes a Superfund site, they’re on the hook financially for the damage they cause.”

Facebook founder and CEO Mark Zuckerberg has said he is committed to curtailing foreign government influence on U.S. politics after initially fighting back against claims his company did not do enough to stop it ahead of the 2016 elections. The company wants to “make this as difficult as possible going forward,” he told USA Today in November.

“We are willing to do whatever we need to do to work on it and solve it,” Zuckerberg said.

The company has publicly pushed the idea that it is reflecting on its role in facilitating political discourse — and that there is still a tremendous amount of work left to cover.

“At its best, [social media] allows us to express ourselves and take action. At its worst, it allows people to spread misinformation and corrode democracy,” Samidh Chakrabarti, Facebook’s product manager for civic engagement, wrote in a blog post in January. “I wish I could guarantee that the positives are destined to outweigh the negatives, but I can’t.”