[Always Right]

I can't find anything that blatantly says who the screenwriter is.

I imagine it was the same person who hire Craig Livingstone.

[scan58]

From another thread:

Elizabeth Egloff, the playwright who wrote the script, admitted to the Times that there was no evidence such a conversation took place. Instead she claims "we know he ducked the issue over and over again, and we know (Nancy Reagan) was the one who got him to deal with it."