Does training the former enemy really work?

Generally it's a quick fix to a problem that usually comes back to haunt us.

Well, seeing as how we've created, funded and trained just about every enemy over the last few decades, I'd say it works really well, at least in terms of ensuring we always have an "enemy" to keep defense funds flowing...

For us, not at all. For them, amazingly. They don't have to rely on observation of we just straight out tell them how we operate. Although, with the military in the condition it is in now, this may turn out to be a mixed blessing to those we are training...