Look at what foreign adversaries are already actively doing: working to turn Americans against each other. Social media is the perfect tool to spread discord. Russia has troll farms that create fake news stories, manipulated photos, and incendiary memes targeted at both sides of the political spectrum. They've even orchestrated in-person protests and counter-protests to those protests, though those efforts have been less successful. Now imagine that instead of merely using fake user accounts to this end, an adversary controlled an entire social network, including its algorithm and its content guidelines and could tailor manipulative content on an individual basis.