Facebook will rely on technology that dates from Ben Franklin’s time to try to combat foreign meddling in future U.S. elections — the postal service.

An executive for the social network told a gathering of the National Associations of Secretaries of State this weekend that the company would begin sending postcards to potential buyers of political ads to verify they reside in the U.S., Facebook confirmed. The postcards would contain a specific code the recipient would enter to complete the purchase.

This approach would apply to ads mentioning a candidate, not issue-based ads.

The policy, which was first reported by Reuters, follows a scathing 37-page indictment Friday that lays bare how Russians working for a firm called the Internet Research Agency used Facebook and Instagram, as well as other social media platforms, to sow discord during the 2016 election and support the presidential campaign of Donald Trump (while disparaging rival Hillary Clinton).

Over the course of two years, the indictment alleges, the Russians stole the identities of Americans to create false personas and operate social media pages designed to manipulate U.S. audiences. The 13 people charged in the indictment bought political ads on social media to achieve their objective, including those excerpts including “Ohio Wants Hillary 4 Prison” and “Donald wants to defeat terrorism . . . Hillary wants to sponsor it.”

The Russians created even bogus Facebook groups, including one, “Being Patriotic,” that was used to coordinate a series of pro-Trump rallies in Florida, according to the indictment. Through false personas, they communicated with local Trump campaign staff, and purchased ads on Facebook and Instagram to promote the political events, the indictment charges. These foreign trolls even coaxed U.S. citizens to perform certain provocative demonstrations for the rallies, such as building a cage on a flatbed truck that would “jail” another person portraying Clinton in prison garb.

Facebook disclosed last fall that the Internet Research Agency had bought ads on its platform, and later acknowledged 126 million people may have been exposed to Russian propaganda. Executives from Facebook, along with those from Google and Twitter, testified before Congress last fall — with some legislators suggesting a need for greater government oversight.

The social network has been working furiously to demonstrate its seriousness in addressing the problem — describing the extent of the Russian ad campaign here and spelling out remedial steps Facebook would take to provide a greater level of transparency in political advertising. 

Facebook also has said it is working hard to improve how it detects fake accounts at the point of creation — noting that it removed tens of thousands of such bogus accounts in advance of last year’s elections in France, Germany and the UK. It’s also doubling, to 20,000, the number of people working on safety and security.

There was a bit of drama over the weekend, as Facebook advertising VP Rob Goldman took to Twitter to challenge the government’s claim that the Russians had been intent on influencing the outcome of the election.

It’s a claim President Trump immediately picked up on a weekend’s worth of angry tweeting.

Facebook’s VP of global policy, Joel Kaplan, issued a statement saying the indictment confirmed what Facebook previously reported about foreign actors conducting a coordinated, sustained effort to attack American democracy. He noted that the social network proactively disclosed this to Congress, the special counsel and the public and has worked to provide a better understanding of what occurred.

“We know we have more to do to prevent against future attacks. We’re making significant investments, including increasing the number of people working on security from 10,000 to 20,000 this year,” Kaplan said in a statement obtained by Deadline. “We’re also continuing to work closely with the FBI, the Department of Homeland Security and other companies on better ways to protect our country and the people on our platform. We’re particularly encouraged by the FBI’s creation of a task force dedicated to addressing election interference, and we are actively working with them. We’re committed to staying ahead of this kind of deceptive and malevolent activity going forward.”