Haugen’s testimony added few new details to her stunning revelations in Washington last month, or to her speech two weeks ago before the British Parliament. But her appearance came at a crucial moment amid a roiling debate in Europe over how to rein in Big Tech, with lawmakers wrestling over proposals that could impose far-reaching regulations on platforms.

The EU’s proposed new law, called the Digital Services Act, or DSA, is up for decision by the bloc’s member countries—potentially bringing significant ramifications for global tech companies. It would strictly limit illegal content, including disinformation, and compel the industry to make more transparent the algorithms that allow it to collect people’s personal data and target content for users.

A companion piece of legislation up for consideration in Europe, called the Digital Markets Act, would curb the ability of giants like Facebook and Google to limit new players trying to enter the market. Big Tech has lobbied furiously against both proposals. In the midst of the fallout from Haugen’s testimony, Facebook last week renamed the company Meta, saying it would focus less on social media and more on the “metaverse.”

Haugen told EU politicians that Europe’s DSA proposals could dramatically change the way Facebook and other tech giants operate, by forcing them to create products that are motivated not primarily by profit, but for users’ safety and well-being.

“If you get the DSA right for 450 million European citizens, you can create a game changer for the world,” she told them. At the end of her three-hour appearance, she said, “I think you guys are really a light in the darkness.”

Two of the DSA’s measures would force platforms to crack down more swiftly on hate and control how they use their algorithms to collect people’s data and social media use—central to the business model of tech platforms.

Perhaps Haugen’s greatest impact in Europe has been showing how those two issues—hate speech and data collection—tie together. In London last month and in Brussels on Monday, she argued that collecting people’s personal data leads directly to hate speech, by amplifying that content among specific groups.

So far, she seems to be convincing Europe’s politicians. Haugen’s arrival in Brussels sidelined a vote on the DSA, which was scheduled for Monday—and which might have shown some divisions among lawmakers, who fear that they might be breaking longstanding principles of free business practices. Julia Reda, a former German member of the European Parliament and an expert in copyright law, wrote in a column on Monday that the DSA could result in “a complete departure from the tried and tested system of limited liability for Internet services and threaten our freedom of communication on the Internet.”

On Monday, however, Haugen found a supportive audience among EU lawmakers. “She’s strengthened the idea that we need strong legislation,” Alexandra Geese, a German member of the European Parliament, told Fortune on Monday after meeting in Brussels with Haugen, and before the crucial testimony. “Coming from an insider, and an American, it’s encouraging Europe to go ahead.”

In that, Haugen’s testimony—even though she said little new from her earlier testimony in the U.S. Congress and the British Parliament—is bad news for the tech industry. A separate proposed law before the French Parliament—where Haugen is scheduled to testify on Wednesday—would stop viral sharing of hate speech and force tech companies to publish yearly risk assessments and make their data available to outside auditors.

The tech industry has argued furiously against the proposals. All told, it spends more than €97 million (about $112 million) a year lobbying lawmakers in Brussels, and hires about 1,452 lobbyists, according to a report in August by Corporate Europe Observatory, which tracks lobbying efforts in the European capital. “This vast firepower indicates that the industry sees a lot at stake in the current policy discussions,” the report says. “The tech firms are outspending all other sectors in terms of lobbying.”

As EU lawmakers have debated tech regulation, industry lobbying efforts have become “extremely intense,” says Geese, a member of Germany’s Greens Party. “There are invitations to dinner,” she says. One of those was from Nick Clegg, Facebook’s vice president for global affairs, while Karan Bhatia, Google’s VP of government affairs and public policy, “showed up in my very modest office in Brussels, and I do not even have a formal role in the negotiations,” she says. “They keep calling and asking for meetings.”

Geese says she believes tech giants like Facebook are attempting to narrow proposed European regulations, focusing on how to stop hate speech and diverting lawmakers from any attempt to limit how tech companies collect and use people’s personal data—something that would hit at the cornerstone of their business models.

“Yes, hate speech is a problem,” says Geese. “But the reason we have so much problem with hate speech is that they [digital platforms] are using personal data to amplify the messages. They know exactly who to send it to.”

Haugen told European politicians that Facebook knows how to change its algorithms, to stop extremist or fake information spreading more rapidly than factual content. “Facebook knows a lot of ways to change the system,” she told them. “But they choose not to, because they will grow less…make less money.”

Correction, November 8, 2021: This article has been updated with a clarification from Alexandra Geese about her meetings with Big Tech executives.