There was a lot of media hysteria about Russian social media trolls (which are a thing, yes, but it's unlikely many people decided to change their vote because they saw a tweet) but the history of "active measures", the sowing of disinformation amongst the citizens of a rival state, has a long history.
The book Active Measures: The Secret History of Disinformation and Political Warfare was an informative deep dive into the modern history of the topic. It starts out with Russian ops between the World Wars, covers the CIA ops in Eastern Europe at the height of its Cold War powers, and yes, it finishes up with the infamous...and overhyped..."troll farm" in St. Petersburg.
"[The author] exposes the disturbing yet colorful history of professional, organized lying, revealing for the first time some of the century’s most significant operations—many of them nearly beyond belief. A White Russian ploy backfires and brings down a New York police commissioner; a KGB-engineered, anti-Semitic hate campaign creeps back across the Iron Curtain; the CIA backs a fake publishing empire, run by a former Wehrmacht* U-boat commander, that produces Germany’s best jazz magazine."
*Don't @ me for his weird usage, Captain Ackshyually. The Kriegsmarine, like the Heer and the Luftwaffe, was an arm of the Wehrmacht.
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