Tuco

I've written before about how Leone doesn't allow his characters to hold true to stereotypes of white = good and dark = bad.  In class, we've talked specifically about Tuco and how interesting it is that this character, the brownest of the three major characters, gets more backstory and a more complex characterization than perhaps any other.  At the time, this was ground-breaking, and I've always seen it as a real mark of Leone's excellence that he would challenge this long-customary western stereotype.  Tuco is the first fully developed Latino character I can remember seeing in a movie of any genre.

But I need to complicate even this because, as ground-breaking as it is, Leone also chooses to cast a white actor (Eli Wallach) in the role, just as John Ford cast a white actor to play the Native American, Scar, in The Searchers (a move we've already talked about when we read Alexie's "I Always Hated Tonto"). 

Why on earth do we make of Leone's choice?  Leone is too intelligent and too aware of his own choices not to have been conscious of the political implications...  What do you make of this?