According to Peter Robinson, a speechwriter, the "line" was discussed and argued about in the US State Department. Some of President Reagan's advisers thought that the line might be seen as provocative by the Kremlin.
At the end, President Reagan said it anyway.
What a great moment it was.
I can still remember holding our 3-week old son and watching it on TV back then.
Did President Reagan see the future? We will never know but he definitely knew that the USSR and the Berlin Wall were doomed for failure. As we know now, The Berlin Wall eventually came down 30 months later!
P.S. You can listen to my show (Canto Talk).