Here is a fascinating Fresh Air interview with David Hoffman. He is the author of The Dead Hand: The Untold Story of the Cold War and its Dangerous Legacy. Interestingly, he paints Reagan as a guy who wanted to make nuclear weapons obsolete - part of the rationale for his Star Wars program. Now this is an intriguing twist to Reagan and I'm still not sure if I buy it completely. It may also represent an evolution of Reagan from his early days to the his second term as President. However, it is clear that Reagan was indeed rattled by the made-for-TV movie The Day After - that imagined the impact of a nuclear attack on Lawrence, Kansas and Kansas City, Missouri. If you don't have time to listen to the whole interview, check out this part of the interview that starts around 28-29 minutes in. From a different perspective, this is an amazing demonstration of the enormous impact television can make (I can also testify to it personally as I decided to pursue astronomy after watching the first episode of Cosmos, when it first aired in Pakistan in 1984). Talking of Sagan, Hoffman's view adds an interesting irony to the anti-nuclear protests in the 1980s. At one point Reagan invited Sagan to a dinner at the White House, but Sagan declined the invitation - partly because of Reagan's Star Wars program. But may be they would have agreed on something. In any case, Reagan did end up borrowing Sagan's aliens. Check out this segment of Reagan's 1987 speech to the UN:
More likely, both Sagan and Reagan were influenced by the story from a 1963 episode of The Outer Limits titled, The Architects of Fear. Watch the full episode here.