Same with Chernenko; apparently Reagan sent him a copy, and along with activists' encouragement, this film got them talking. More importantly, the movie so influenced the Cold War leaders that it prompted the 1986 Reykjavik Summit that nearly cleared the world of nukes.
Imagine how things might have gone if that had happened. Would North Korea, India, Pakistan, China, and everyone else have felt the same drive to build their own nukes if the US and USSR had dumped theirs? We'll never know, because Reagan was too much of an idiot to not realize we didn't already have a Star Wars-like missile defense in place.
The point I want to make is that science fiction can save the world, and here's the evidence. People like Reagan simply couldn't imagine the fallout of catastrophic decisions. But seeing the result of the decision to launch a nuclear war - watching the characters in the movie suffer - provided the imagery he needed to understand that it was a bad idea. That a nuclear war was not winnable.
Science fiction: Saving the world one person at a time.