The Kremlin uses both conventional media — Sputnik, a news agency, and RT, a television outlet — and covert channels, as in Sweden, that are almost always untraceable.

Russia exploits both approaches in a comprehensive assault, Wilhelm Urme, a spokesman for the Swedish Security Service, said this year when presenting the agency’s annual report. “We mean everything from internet trolls to propaganda and misinformation spread by media companies like RT and Sputnik,” he said.

The fundamental purpose of dezinformatsiya, or Russian disinformation, experts said, is to undermine the official version of events — even the very idea that there is a true version of events — and foster a kind of policy paralysis.

Disinformation most famously succeeded in early 2014 with the initial obfuscation about deploying Russian forces to seize Crimea. That summer, Russia pumped out a dizzying array of theories about the destruction of Malaysia Airlines Flight 17 over Ukraine, blaming the C.I.A. and, most outlandishly, Ukrainian fighter pilots who had mistaken the airliner for the Russian presidential aircraft.