As public trust in Facebook’s ability to wield its power responsibly has fractured in the face of a series of privacy breaches and other scandals, the company has been facing fresh calls for regulation from numerous quarters of the federal government.

But on one of the biggest issues leading to that breakdown of trust, its response to foreign election interference, Facebook has made significant progress, according to Chief Executive Mark Zuckerberg, who made a rare public appearance at the Aspen Ideas Festival on Wednesday.

In a discussion with Harvard Law School professor Cass Sunstein, Zuckerberg invited regulators to set industrywide privacy standards and take a harder line with foreign interference in elections while pushing back against calls to break up Facebook.

“Results in elections have been a lot cleaner online due to a lot of the work we and others have done in partnership,” Zuckerberg said. Still, he said, there are decisions about what constitutes acceptable political speech and advertising that Facebook, as a private company, should not be making by itself.

“Whether regulation comes in the form of democratic process, legislation or industry self-regulation, we’re past the point where it makes sense for Facebook to unilaterally make these decisions,” he said.

To combat misinformation, the company has hired 30,000 people whose jobs include reviewing content for accuracy. Rather than take down content determined to be false, moderators mark it as inaccurate, disable any significant distribution of that post and offer users more accurate alternative sources as context.

But these tactics, even paired with “sophisticated AI systems” the company has built to detect misinformation campaigns, aren’t sufficient to combat foreign interference akin to what was seen during the 2016 presidential election, according to Zuckerberg.

“It’s an arms race,” Zuckerberg said. “Russia and other folks have also gotten much more sophisticated…. We’ve seen new tactics.

“We can defend as best as we can but our government is the one that has the tools to apply pressure to Russia, not us,” he said. “One of the mistakes I worry about is that after 2016 when the government didn’t take any kind of counter-action the signal that was sent to the world was, OK, we’re open for business.”

Adding to the difficulty of reining in misinformation, social media platforms are being forced to grapple with the relatively new threat of so-called deep fakes, often realistic video or audio that is fabricated using artificial intelligence. Zuckerberg said the company is currently “evaluating” its policies around deep fakes and indicated they might fall into a category of their own. “I think it’s likely sensible to have a different policy and to treat this differently than how we treat normal false information on the internet,” he said.

“I think that we need to make sure in doing this we define what deep fakes are very clearly,” he said. “Is it … manipulated media using AI that makes someone say something that they didn’t say? I think that’s probably a pretty reasonable definition.

“But, I think you want to make sure you’re scoping this carefully enough that you’re not going to be giving people the grounds or precedent to argue that the things they don’t like that maybe change the meaning somewhat of what they said get taken down,” he said.

As the company faces potential antitrust investigations by the Federal Trade Commission and the House Judiciary Committee, calls to break up Facebook have joined scrutiny of its content moderation practices. Hours before Zuckerberg’s appearance, President Donald Trump suggested the U.S. government should sue social media companies like Facebook. The president didn’t indicate what he believed the government should sue the companies over but cited alleged biases against conservatives on their platforms.

As for Facebook’s size, Zuckerberg echoed his previous arguments that breaking the company up wouldn’t solve any problems and would, in fact, make existing problems harder to fix.

“The amount we’re investing in safety and security is greater than the whole revenue of our company when we went public,” he said. “It just would not have been possible to do what we’re doing at a smaller scale.”