Over the last two days, Facebook CEO Mark Zuckerberg was questioned for more than 10 hours by two different Congressional committees. There was granular focus on privacy definitions and data collection, and quick footwork by Zuckerberg—backed by a phalanx of lawyers, consultants, and coaches—to craft a narrative that users “control” their data. (They don’t.) But the gaping hole at the center of both hearings was the virtual absence of questions on the tactics and purpose of Russian information operations conducted against Americans on Facebook during the 2016 elections.

Here are the five of the biggest questions about Russia that Zuckerberg wasn’t asked or didn’t answer—and why it’s important for Facebook to provide clear information on these issues.

1. What were the tools and tactics used by Russian entities to execute information operations against American citizens, and what were the narratives pursued?

In both hearings, in answering unrelated questions, Zuckerberg began to describe “large networks of fake accounts" established by Russian entities. In both instances, he was cut off. This was a significant missed opportunity to pull back the curtain on the mechanisms of Russian information operations against the American public.

The vast majority of information made available by Facebook—and the focus of questions in response—have been about ads and promoted content from Russian entities like the Internet Research Agency. In fact, this was not the primary means of distributing content, collecting information, identifying potential supporters, and promoting narratives. The main tool for this was fake accounts posting "native" content—plain old Facebook posts—building relationships with real users.

In Wednesday’s hearing before the House Energy & Commerce Committee, for example, Zuckerberg said that tens of thousands of fake accounts were taken down to prevent interference in elections in 2017, implying that this was mostly relating to Russia. But this wholesale removal of accounts obviously went way beyond the 740 accounts that have been identified as buying ads on behalf of the IRA. Zuckerberg focused only on ads bought by Russian accounts, not the regular Facebook posts that were so much more numerous. He testified that the Russian accounts were primarily using “issues ads”—aimed at influencing people’s views on issues rather than promoting specific candidates or political messaging. Asked about the content though, Zuckerberg said he had no specific knowledge.

In the indictment of the IRA, prosecutors highlighted the fact that the agency had used false IDs to verify false personas. So, while Facebook's announcement that group pages will now require verification with a government ID and a physical address that can be validated, fake IDs and the use of US-registered shell corporations (a point raised by Senator Sheldon Whitehouse) can be used to bypass these security protocols—albeit with a much more significant expenditure of resources.

Zuckerberg said Facebook only identified Russian information operations being conducted on their platform right before the 2016 elections. But in his written testimony, he says they saw and addressed activity relating to Russian intelligence agencies earlier. And from 2014 onward, Facebook was made aware of the aggressive information campaigns being run against Ukraine by Russia.

It wasn't an accident that Zuckerberg used the term "sophisticated adversaries" in his prepared statement. Facebook, more than anyone, has visibility into what Russia does and why it works. Apparently, no one was interested in hearing what he had to say.

2. What personal data does Facebook make available to the Russian state media monitoring agency Roskomnadzor or other Russian agencies? Is this only from accounts located in or operated from Russia, or does this include Facebook's global data?