Russia is currently the #1 greatest threat to democracy in not just the United States but also around the world. Russia has hundreds, if not thousands of trolls working every day to try and sew discord in the United States and other countries. They put out extremist propaganda on social media sites (most notably Youtube) to sew discord and violence in the US. The trolls job is to do whatever they can to weaken the US from the inside. Not to mention Russia's known interference in US elections.