Facebook has released to Congress a batch of pre-election ads that have been traced back to Russian propaganda sites. According to the Washington Post, the Russian government used Facebook to attack America in a very direct way by striking along the weakest points of the national character: racism and religious prejudice.

The batch of more than 3,000 Russian-bought ads that Facebook is preparing to turn over to Congress shows a deep understanding of social divides in American society, with some ads promoting African-American rights groups including Black Lives Matter and others suggesting that these same groups pose a rising political threat, say people familiar with the covert influence campaign.

In what may be the saddest commentary about the state of the nation, even Russia understood that portions of the American electorate could be manipulated over issues of race and religion. With the deep demographic targeting available through Facebook, Russia was able to deliver to critical voters a message that far too many saw as negative—Hillary Clinton was the favored candidate of blacks and Muslims.

“The idea of using Facebook to incite anti-black hatred and anti-Muslim prejudice and fear while provoking extremism is an old tactic. It’s not unique to the United States and it’s a global phenomenon,” said Malkia Cyril, a Black Lives Matter activist in Oakland, Calif. and the executive director for the Center for Media Justice. Social media companies “have a mandate to standup and take deep responsibility for how their platforms are being abused.”

The story that Russia tells about America—including the way America is discussed within Russia—is that the United States is a land of unequal justice and vast racial disparity. In their Facebook ads, they turned that theory into a weapon.

Highlighting racial tensions isn’t just a way for Russia to hold itself up as better than the United States. It’s a way that the Soviet Union sought to promote divisions within the United States, going back to before the Civil Rights era. But adding Facebook to the mix turns clumsy efforts into precision-guided weapons that land on individual voters.

The social network invested heavily in building highly-sophisticated automated advertising tools that could target specific groups of people who had expressed their preferences and interests on Facebook, from newlyweds who studied at Dartmouth College to hockey enthusiasts living in a particular zip code in Michigan.

With the ability to show different ads to different people, Facebook made it possible to target rural voters with ads that associated Hillary Clinton with the Black Lives Matter movement. Or showcase Hillary’s support among Muslims to evangelical Christian voters. It was a method of not just driving down support for Hillary, but driving up fervor among those who came out simply to vote against her.

The same tools that make it possible to show people the things they might like to buy make it equally possible to associate people with the things they distrust, the things that make them uncomfortable, the things they hate.

Facebook has said that one-quarter of the ads bought by the Russian operatives identified so far were targeted to a particular geographic area.

Though that area hasn’t been identified, it’s possible to make a good guess.

Watts said such efforts were most likely to have been effective in mid-Western swing states such as Wisconsin and Michigan, where Democratic primary rival Sen. Bernie Sanders had beaten Clinton. Watts said the disinformation pushed by the Russians includes messages designed to reinforce the idea that Sanders had been mistreated by the Democratic Party and that his supporters shouldn’t bother to vote during the general election in November.

Voters in Midwestern states, many of whom had already internalized the idea that Hillary was too associated with “identity politics,” had that message reinforced by targeted ads developed by propaganda specialists within the Russian government. Those ads were expressly designed to increase concerns over race and religion. That may have been particularly effective, even among Democratic voters, in these states.

Schaffner found that what distinguished Sanders-Trump voters from Sanders-Clinton voters wasn’t their attitudes about trade, but their attitudes about race. When asked whether whites are advantaged, Sanders-Trump voters were much more likely to disagree than were Sanders-Clinton voters.

Russia put a crowbar into an already existing crack. And pushed it wide open.