On another thread I posted a week ago 'An option overlooked' after Fuchs rightly posted his succinct observation, with my emphasis:
The Americans never really mastered this indirect rule and the setup of effective indigenous sepoy-like forces either.
This is an issue which has always interested me and IMO deserves its own thread. As always this opening post will drop down when other, earlier posts are copied here.

I am very aware that for the USA there has been a long history of involvement in setting up such local forces; post-1945 it became an SOF responsibility and in various modes is undertaken today.

The big difference in this thread is 'sepoy-like', so I mean locally recruited with expatriate officers and NCOs. Not advisory teams, embedded and more recent descriptive terms.