Until they cut them off the internet, they won't be able to. There are ways to reduce exposure to it.
Eg: I am floored, that the US would use electronic polling stations, and would not deeply protect things like connections from those stations to the Polling Register. TX announced today that Russia did target their voting register. All 50 states are expected to report the same publicly today. Why were these addresses publicly known? Not firewalled? No VPN? #ItMakesMeCrazy
I read another story on CBC just now about the Russian propaganda that is being spread into Latvia over the NATO forward-deployment. Some of it, is pretty low and disgusting.
http://www.cbc.ca/news/world/latvia-propaganda-1.4162612
But that's exactly what they want. They want the Latvians (native Russian speakers) to read this absolute garbage and believe all or even some of it. It's the cold war propaganda machine v. 2.0