Could screening the social media of US visitors help prevent terror attacks?

The Department of Homeland Security has proposed asking foreign visitors to disclose their social media information. 

Could screening the social media accounts of foreign visitors to the US help thwart terror attacks? 

The Department of Homeland Security (DHS) may soon be doing just that.

In a notice by US Customs and Border Protection published in the Federal Register last week, the agency proposed adding a line to forms filled out by visitors to the US asking them to voluntarily disclose their social media information.  

"Collecting social media data will enhance the existing investigative process and provide DHS greater clarity and visibility to possible nefarious activity and connections by providing an additional tool set which analysts and investigators may use to better analyze and investigate the case," the notice read. 

The proposal will now undergo a 60-day comment period, ending August 22, for the public to weigh in. 

The Islamic State has notoriously used Twitter to recruit supporters, both in America and around the world. As The Christian Science Monitor's Molly Jackson reported in December: 

...The growth of social media has made terrorism propaganda not only more accessible – "the terrorist is in your pocket," as FBI director James Comey told the Senate this summer – but more personalized for each Twitter user, increasing the chances he or she could be 'groomed' for recruitment. 

At least 46,000 Twitter accounts are maintained by IS supporters, according to a March 2015 report from The Brookings Project on US Relations with the Islamic World, although a mere 500 to 2,000 contribute the bulk of its online activity. 

Considering the documented use of social media by the Islamic State, some lawmakers say the DHS's proposal isn't enough. 

Legislation currently pending in Congress would make disclosure of social media information mandatory for foreign travelers, requiring the DHS to review all public records, including Facebook and other social media, before admitting visitors to the US. 

Rep. Vern Buchanan (R) of Florida, who introduced one such bill in the House, called the DHS proposal for optional screening "lame."

"What terrorist is going to give our government permission to see their radical jihadist rants on social media?" Rep. Buchanan asked in a press release. "The only people who will share that information are those with nothing to hide." 

While the DHS doesn't consistently look at the social media accounts of people applying for visas or immigration, it does have a list of nearly three dozen situations in which it can use social media to screen applicants, according to The New York Times. 

There are also four pilot projects currently underway for the department to study social media use among people applying for immigration benefits. One of the projects, which began in December and runs through this month, screens the social media accounts of those applying for fiancé(e) visas. (One of the attackers in the December shooting in San Bernadino, Calif. entered the US with such a visa.)