I would have read this book ca. 1975. My memory was that it was by Ben Bova, but I think that must be wrong, because I spent some time searching through descriptions of his books, and I couldn't find this.
The story is set on a moon colony. I think there are separate US and soviet colonies. The year is about 2000. Conflict is brewing on earth between the US and USSR over resources (fossil fuels?) in Antarctica. Because the author is writing in 1975 and is so hip, there is social marijuana smoking in the US lunar colony. The main protagonist is the commander of the US colony.
I think the climax of the book involves the US commander having a heart attack or stroke.
Can anyone identify this book for me?