Blackwater was quite well known in Iraq War. How can we have private military contractors helping (or messing) regular armies in, say, World War 2 or Cold War proxies?
Perhaps my understanding of history is flawed, then, because I had always thought mercenaries had quite a long history of being accepted and legal. Straight off the top of my head the Roman empire used mercenaries extensively, as did the Greeks, there were the condottieri in middle-ages Italy, and closer to the present we have the Gurkhas. I'm sure there are countless other examples as well of mercenaries who not only were accepted as combatants but did so legally. Perhaps I should ask a different question: what is the difference between a mercenary and a PMC? Because just looking those terms up on wikipedia is giving me a striking feeling of deja vu.