Lawmakers have resurrected legislation that would require tech companies to report online terrorist activity following the mass shooting in San Bernardino last week. The "Requiring Reporting of Online Terrorist Activity Act" would force firms like Facebook and Twitter to tell law enforcement if they "become aware of terrorist activity" on their networks. Senator Dianne Feinstein, the vice chairman of the Senate Intelligence Committee, has introduced the bill along with the committee's chairman Richard Burr. In a press release, the senators note that one of the San Bernardino shooters, Tashfeen Malik, is reported to have declared her allegiance to ISIS on Facebook at around the time of the attacks.

"We’re in a new age where terrorist groups like ISIL are using social media to reinvent how they recruit and plot attacks," said Feinstein in a press statement. "That information can be the key to identifying and stopping terrorist recruitment or a terrorist attack, but we need help from technology companies. This bill doesn’t require companies to take any additional actions to discover terrorist activity, it merely requires them to report such activity to law enforcement when they come across it."

Feinstein has stressed that the legislation would not require tech companies to undertake any additional monitoring of individuals, adding on Twitter that the bill "does not criminalize free speech." However, it's difficult to judge the exact impact the laws might have without more detailed information about the reporting procedure and what constitutes "terrorist material." While the bill's wording makes it clear that tech companies would only have to report activity "when they become aware of it," it's not clear what counts as "awareness" — could, for example, email providers be asked to passively scan the content of messages to look for certain content? Gmail, for example, already scans all of its emails for child porn, and Feinstein's bill is based on the legislation that requires the company to do so.

This legislation was original suggested earlier this year but its backers were pulled up short when Senator Ron Wyden placed a procedural hold on the bill it was part of. Wyden's office criticized the bill as "vaguely defined," with Wyden stating: "Social media companies aren’t qualified to judge which posts amount to 'terrorist activity,' and they shouldn’t be forced against their will to create a Facebook Bureau of Investigations to police their users’ speech." Tech companies including Facebook, Google, and Twitter also slated the bill, saying it would introduce an "impossible compliance problem," and result in the "reporting of items that are not likely to be of material concern to public safety," according to a report from Ars Technica.

There's no doubt that the events in San Bernardino have sparked new debates (and reignited old ones) about the role of tech companies in helping to identify terrorists. But in the case of Tashfeen Malik and her husband Syed Rizwan Farook, it's not clear what difference the involvement of social networks could have made. Some reports have said that Malik's "pledge of allegiance" to ISIS was only posted to Facebook after the attacks began and was made using a pseudonymous account. The post was removed by Facebook the same day.

Despite the difficulties of policing the internet for terrorism-related content (for example, social networks often rely on users' own reporting, which isn't so useful if the content is being shared by like-minded people), political support for tighter web controls continues to grow. Although Donald Trump has been mocked for suggesting the US could "close up" the internet to curb the spread of terrorism, his views are not far from those of Hillary Clinton. Both Trump and Clinton have preemptively waved off objections about "free speech," and seem determined to press for more action, of any sort. If Feinstein and Burr's bill emerges from committee and ends up being voted on then it's likely to find support.