Isn't it confirmed that the Russians hacked the DNC e-mails on the day that Trump famously said: 'Russia, if you're listening...". Wasn't that in the indictment for the 12 members of the GRU?
https://www.theguardian.com/us-news/2018/jul/13/russians-hil...
Email? Nope, it might go to the spam folder.
Phone call? What of the time zone difference?
Blinking morse code? Too obvious!
Secret gesture? The FSB may miss it!
Literally giving out the order on international TV during debates? Sounds like a plan!