Troubled Futures: The Mercenary by Jerry Pournelle — Alan Brown at Tor.com
The Mercenary, by Jerry Pournelle, was published in 1972 and is very much of its era. The setting is centuries in the future, during the collapse of the CoDominium, an interstellar civilization founded jointly by the US and USSR, who still hate and fear each other but hate and fear the rest of the world more. The hero is Col. Falkenberg, who’s trying his best to keep civilization, and his mercenary legion, going a little while longer in some corner of space.
It occurs to me that “For All Mankind” can be viewed as a prequel to the CoDominium stories.