People misunderstand me a lot (probably my fault!) when I "go there" but the Dems are not going win in 2018 on "Russia." That's entirely about the politics, not the substance of any actions, crimes, coverups, investigations, etc. And the problem with screaming "Russia" since the day after election day, 2016, is that most normies have tuned out on the issue by now. You might like your cannon booms, but eventually things just become background blather. The people you need to get to vote in midterm elections - the people who are less likely to vote, generally - are the people who tune out politics most of the time, the lucky souls. What did "Russia" do to me? Nothing. What are the Dems going to do for me? ...
And it doesn't help that Dems keep trying to appeal to non-existent "reasonable Republicans" instead of tying Trump around their necks about everything, including Russia.