In the sepia-toned photo, two white soldiers patrol on foot over brush and rocky ground. Lean and bearded, they carry what appear to be Belgian rifles, and they wear an unusual uniform — cloth jungle hats, short shorts and tennis shoes — associated with a military unit that was disbanded nearly 40 years ago.

That unit was called the Selous Scouts, a special-forces regiment from the Rhodesian Army, which fought black insurgent armies in the Bush War of the 1960s and ’70s to maintain white-minority rule over territory that is now Zimbabwe.

Not long after Rhodesia ceased to exist, it became morally untenable to mourn its disappearance. As the rest of the world woke up to the injustices of Western colonialism and its system of white-minority governments, the Selous Scouts and their cause became taboo.