The Russian bots are already at work.
I'm absolutely convinced they're behind the "Bernie-bro" shit that derailed Bernie's campaign and instigated the Bernie-Hillary wars.
They played both sides against the middle - deliberatly make "pro-Bernie" misogynistic troll attacks, then switch to different personas and scream that anyone who supported Bernie at all obviously hates all women.
See how this works?
Right now, IIRC, they're targeting Kamala Harris, Bernie Sanders (of course,) Elizabeth Warren, and Beto O'Rourke.
And I would not be surprised if they start spamming DU as well. I'm 100% certain they were right here in 2016.
Here's an article about that:
https://theweek.com/speedreads/824704/theres-already-ferocious-nebulous-social-media-campaign-undermine-4-democratic-presidential-hopefuls