https://www.nytimes.com/2018/12/17/us/politics/russia-2016-influence-campaign.html

Backfire effect says people (of all races) who were scammed will now say “Others may have been scammed, but *I* voted for the candidate I thought was best suited” or “… but *I* honestly believe no candidate would be good, so I didn’t vote.”

Of 81 Facebook pages created by the Internet Research Agency in the Senate’s data, 30 targeted African-American audiences, amassing 1.2 million followers, the report finds. By comparison, 25 pages targeted the political right and drew 1.4 million followers. Just seven pages focused on the political left, drawing 689,045 followers.

While the right-wing pages promoted Mr. Trump’s candidacy, the left-wing pages scorned Mrs. Clinton while promoting Senator Bernie Sanders of Vermont and Jill Stein, the Green Party candidate. The voter suppression effort was focused particularly on Sanders supporters and African-Americans, urging them to shun Mrs. Clinton in the general election and either vote for Ms. Stein or stay home.

Whether such efforts had a significant effect is difficult to judge. Black voter turnout declined in 2016 for the first time in 20 years in a presidential election, but it is impossible to determine whether that was the result of the Russian campaign.