1. Nate is probably correct here, but I do want to share the impact that "fake news"--some of it homegrown like Breitbart but much of it manufactured abroad (like "Pope endorses Trump")--had on my little FB circle.
2. I grew up in central PA in a small town that went hard for Trump, but was blueish-purple in the 80s when I grew up there. In the early 2010's I had reconnected with a politically diverse set of about 50 friends from my HS, almost 25% of my graduating class.
3. Until the election of 2016 we didn't engage about politics, but in the summer things started to heat up. Much of the conversation was civil, but sometimes it could get heated. It helped that we all had known each other since we were 6 years old & thus had a baseline of trust.
4. What finally split that FB community of former HS pals was a fundamental epistemological break over what was real and what wasn't. A Trumper would post an obviously fake story. A non-Trumper would point out the fakeness, and the Trumper would deny, deny, deny.
5. Someone would bring in Snopes or some other fact checker as an arbiter, and the Trumper would post a fake story "proving" that Snopes was funded by the DNC and maybe Soros, and thus it had no standing.
6. Someone would cite the NYTimes or WaPo and the Trumper would immediately scoff and say "I don't believe a word they say. They're biased." And then they would post a meme from libtardssuck doc com about the Pope endorsing Trump.
7. I and other non-Trump friends would try to reason with such folks...do the whole "media literacy 101" thing distinguishing bias from perspective, encouraging folks to consider the source of the information...but it was no use.
8. In the span of 6 months my politically diverse group of HS friends on FB bifurcated into three groups "the libtards" (the group I was a part of, apparently), "the patriots," and the people who just stayed out of it and posted pictures of their pets and kids.
9. Russian disinformation didn't "cause" this irreconcilable breach to open up within this HS FB friend group, but I have little doubt that it was a significant contributing factor. It helped transform "I think you're wrong about X" into "I think you're deluded about everything."
10. BTW, that FB breach has not healed. Folks in that small town I grew up in are hesitant to talk about current events with each other these days unless they're sure they know where the folks they're talking to stand. The divisions and suspicions have been chilling.
11. Meanwhile, the old HS Trumper friends I used to amicably spar with on FB have all retreated from engaging across the divide...as have I. Those folks were never going to vote for Hillary. But they didn't used to think Democrats were the antichrist. Many were Obama voters.
12. I think it's also worth mentioning that several of my HS friends recirculated anti-HIllary screeds posted by fake, Black conservative FB accounts. These white Trumpers were drawn to those posts because they "proved" that neither they nor Trump were racists.
13. So when we think about the way "fake news" deployed race in the 2016 election, it's worth noting that this was one strategy...to convince well-meaning, rural white conservatives that voting Trump was not racist, because a black person on FB had said so.
14. These are the racial demographics of that county. The only contact most of these white Trump voters have with people of color on a regular basis is through strangers on social media or on TV. They chanted "build the wall" with glee...yet they've never met a Mexican-American. 
15. To circle back to Nate Silver, I think quantitative methods (his forte) will never be able to tell us if Russian disinfo shaped the election outcome. But qualitative methods (such as those I've deployed on a small scale here) might be better equipped to offer insights.
