WASHINGTON — After two days and more than 10 hours of questioning of Mark Zuckerberg, the Facebook chief executive, there was widespread consensus among lawmakers that social media technology — and its potential for abuse — had far outpaced Washington and that Congress should step in to close the gap.
But the agreement largely ended there. For lawmakers, the calculus is tricky: They do not want to infringe on First Amendment rights or hurt Silicon Valley innovation but are also unsure how to regulate this new breed of company, which wields enormous power by collecting vast amounts of private data from billions of consumers.
“While Facebook has certainly grown, I worry it has not matured,” said Representative Greg Walden, Republican of Oregon and the chairman of the House Energy and Commerce Committee. “I think it is time to ask whether Facebook may have moved too fast and broken too many things.”
Mr. Zuckerberg, composed but noncommittal about making any sweeping privacy changes, conceded that it was “inevitable that there will need to be some regulation.”
The growing calls for regulation — and the two days of congressional hearings — were prompted by revelations that Facebook failed to protect the sensitive data of as many of 87 million users from being harvested, without their explicit permission, by Cambridge Analytica, a political consulting firm linked to the Trump campaign. But lawmakers’ concerns extended beyond that breach to the business of Facebook itself, a free social network that profits by collecting data from its users and selling advertising that is informed by that data.
“The American people are concerned about how Facebook protects and profits from its users’ data,” Mr. Walden said. “Does Congress need to clarify whether or not consumers own or have any real power over their online data?”
Whether Congress can actually mobilize to put new controls into place is an open question. This week, two privacy bills were introduced to coincide with the hearings. One would make it harder to collect data on students who use classroom technology like tablets and laptops. Another would require companies to obtain clear permission from users before collecting and sharing their data.
At least three lawmakers have said privately that they are drafting new privacy laws for internet companies. Representative Marsha Blackburn, Republican of Tennessee, for instance, is pushing a bill she introduced last year that would require broadband providers and internet companies like Facebook to get permission before sharing user data. And late Wednesday, Facebook said it would drop its opposition to the California Consumer Privacy Act, a state ballot measure meant to offer consumer protections for personal information.
House members repeatedly pummeled Facebook over its user settings, many of which are currently set to share information — and not to keep that data private — by default. By contrast, European rules that will take effect next month are expected to push companies to make privacy the default option.
On Wednesday, Ms. Blackburn pressed Mr. Zuckerberg about whether he would support her legislation, asking: “Who do you think owns an individual’s presence online? Who owns their virtual you? Is it you or is it them?”
With more contrition and promises to work harder to protect consumers, Mr. Zuckerberg stayed close to the prepared talking points he has used since the breach came to light. “It will take some time to work through all of the changes we need to make, but I’m committed to getting it right,” he said.
Mr. Zuckerberg also revealed that his own personal data had been compromised by third-party actors, though he did not identify which company was responsible. He said Facebook was considering legal action against Cambridge Analytica.
His testimony did little to mollify lawmakers, who called for new regulations that would limit Facebook’s ability to collect data on users without permission and to make privacy policies clear to better empower consumers.
“This incident demonstrates yet again that our laws are not working,” said Representative Frank Pallone Jr. of New Jersey, the top Democrat on the House committee.
Despite the consensus that legislation is needed, there is no clear path forward on any of the proposals. The regulation most likely to pass after the hearings is a Senate bill that would require social media companies to disclose funding of political ads on their sites.
Facebook and Twitter have recently announced their support of the bill, called the Honest Ads Act, which is modeled after disclosure rules for broadcasters. Several internet companies, including Facebook, had lobbied aggressively to defeat any new rules for online political ads, but have since changed their positions.
For many lawmakers, even defining what Facebook is and how to place it within the regulatory ecosystem was a challenge.
“What exactly is Facebook?” Mr. Walden asked, listing industries like advertising, publishing and even telecommunications, asking whether the company was a “common carrier in the information age.”
The definitions matter. If Facebook is viewed as a telecommunications service that is more like a utility, it may be regulated by the Federal Communications Commission. If lawmakers define Facebook as a publisher, it could also fall under regulations at that agency.
Mr. Zuckerberg was careful not to put his company in a clear regulatory category.
“I consider us to be a technology company,” Mr. Zuckerberg replied. Facebook should be responsible for what it publishes, he said, but it was not a news media company. “The primary thing we do is have engineers that write code and build services for other people.”
But the hearings helped create a foundation for new rules in the future, experts said. Congress showed an increasing ease — particularly from important Republicans in both chambers — to regulate Silicon Valley.
“Longer term, we saw growing comfort on both sides of the aisle for privacy legislation,” said Alan Davidson, a former internet policy official in the Obama administration and a former executive at Google. “So this is not the last we’ve heard from Washington.”
For Mr. Zuckerberg, who has been warmly welcomed by world leaders in China and India, it was clear that Facebook had few friends in Washington, particularly in the House. The company has invested heavily in its lobbying of Congress and the administration. Lobbying expenditures in 2017 increased 32 percent to $11.5 million from the previous year. But it has struggled to shake impressions among some Republicans that the site and its employees have a liberal bias. Democrats who were once close to Silicon Valley have become vocal critics of social media platforms for allowing fake political news and foreign interference in the 2016 presidential election.
On Wednesday, House lawmakers from both parties took an aggressive stance toward Mr. Zuckerberg, pointing fingers, interrupting and chastising him for repeated failures — and apologies — over privacy.
Representative Jan Schakowsky, Democrat of Illinois, used a sizable chunk of her limited speaking time to list Mr. Zuckerberg’s past apologies.
Representative Bobby L. Rush, Democrat of Illinois, repeatedly pointed a finger at Mr. Zuckerberg when asking, in a raised voice, “Why is the onus on the user to opt in to privacy and security settings?”
Representative John Sarbanes, Democrat of Maryland, cut off Mr. Zuckerberg several times as he tried to answer a question about Facebook employees who sit with political campaigns as “embeds” and seek to get the campaigns to use the site for advertising.
The second day of marathon hearings came after more subdued questioning from the Senate. But some key Republican senators also signaled a desire for regulations on Silicon Valley.
Senator Lindsey Graham, Republican of South Carolina, said after the hearing on Tuesday that Facebook was a “virtual monopoly” and that “continued self-regulation is not the right answer when it comes to dealing with the abuses we have seen on Facebook.”
The hearings also revealed lingering suspicion of Facebook among Republicans. Out in the hall during a break in the hearing, Representative Billy Long, Republican of Missouri, expanded on his remarks about Facebook’s treatment of Diamond and Silk, two pro-Trump video personalities who have complained about being censored by the platform. The online personalities were brought up numerous times on Wednesday.
“It seems like they take down a lot more conservative content than they do liberal,” Mr. Long said.
Mr. Long said that he needed more answers about the particular situation, and that he hoped Mr. Zuckerberg could ensure that the company’s thousands of moderators were not biased against conservatives.
“He better hope he does it, not us,” Mr. Long added. “Or Congress is going to get involved, and regulate a private industry.”