See if this sounds familiar: a strange name pops into your twitter mentions, using violent photos and provocative language to force the conversation off-track. You start out talking about something innocuous, but by the end, you're being challenged to shore up your whole view of the world or admit defeat. Suddenly, you're under assault.

Find enemies of the state, and troll them

This, roughly, is how a troll works. They're common tactics, but effective ones, and recently they've found an unexpected home: the US State Department. In January, the department launched @ThinkAgain_DOS, an English-language version of similar accounts that were already running in Arabic, Somali, and Urdu. The official name is the Center for Strategic Counterterrorism Communications, and the mission is simple: find users sympathetic to enemies of the state, and troll them until they see the error of their ways.

"The first thing we do is listen, to look and see, where is the adversary having these conversations?" says Ambassador Alberto Fernandez, who coordinates the program. "And that's where we want to go." For a surprising number of extremists, that means Twitter. The US has infiltrated or taken down most of the password-protected forums where these sentiments used to take hold, and the same conversations have moved on to public platforms. Fernandez says last year was the "year of Twitter" for al-Qaeda, particularly in English, which left the program little choice but to follow them onto the service.

"It's targeted at blunting the recruitment pitches."

@ThinkAgain_DOS doesn't have many followers (just 1,552 at press time), but it's not designed for people to actually follow it. It's a disruptor, replying to accounts that don't follow it and breaking up hashtags like #ISIS or #BokoHaram, the names of designated terrorist groups in Iraq and Nigeria. As a former State Department adviser described it to Mother Jones, "it's targeted at blunting the recruitment pitches." That means busting up the conversation. The replies are often shocking, using pictures of dead soldiers and beheaded civilians — but what they're replying to is often just as shocking. "Talking about al-Qaeda, comparing the difference between what they say and what they do, is very effective and we do that all the time," Fernandez says.

Sometimes it's more complicated. In one recent example, the account seized on a tweet about Aafia Siddiqui, a Pakistani neuroscientist and mother of three who’s currently in custody for alleged links to al-Qaeda. The account isn't influential — it boasts only 10 followers — but the #aafiasiddiqui hashtag was enough to set things off.

Is that what a successful mission looks like? As the people behind the account are quick to admit, it can be hard to tell whether an exchange has actually changed someone’s mind — but the larger point is just to disrupt the extremist narrative, in the tradition of classic counter-narrative operations like Radio Free Europe. The arguments might not change minds, but as long as they break up the drumbeat of anti-American sentiment, the account has done its job.

And like most Twitter accounts, it’s cheap. Unlike the more ambitious State Department ops, Fernandez’s project can be run with just a few linguists with laptops. It’s cheap enough to follow the conversation wherever it goes — so if pro-Assad forces start fostering dissent on Pinterest tomorrow, the State Department will be right behind them. It’s not strong enough to control the conversation, but it’s strong enough to complicate it. As the ambassador puts it, "What we do is not industrial, it's more artisanal."