The Russian troll army was very clever in using US racism to convince blacks not to vote.

That was the Republicans' first line of defense against black voters. The second line was voter suppression, and the third, gerrymandering.

The Russian ad campaign exploited a problem that the US really has: plutocratist politicians tend to be mostly interested in the voters only at election time. That is mostly true but not 100% true, and racism is one of the injustices that plutocratists Democrats do make some efforts to reduce — but only in the ways that the banksters don't veto.