The only people who took seriously the idea of a Shuttle FOBS were the Soviets, and frankly not even all of them; as far as I've ever seen credible evidence to substantiate, it never went much past a single position paper from the early 80s. The idea that Buran was meant as a MAD-restoring FOBS has, so far as I know, not even that much support. (If you know of primary sources, in translation or otherwise, please link them.)

Read Payne Harrison's 1989 novel Storming Intrepid, followed by NASA publication SP-4221, "The Space Shuttle Decision," from 1999. [1] The first is a pretty good depiction of what you're imagining, and the second explains why the imagination of a technothriller author is where that idea went to die. Then maybe give your head a shake. If Reagan had violated the Outer Space Treaty - via NASA of all agencies! - how do you imagine it'd have stayed secret over these forty years just past?

[1] https://web.archive.org/web/20241229052235/https://ntrs.nasa...