How would things be different with Native South Americans if the Spanish never came?

[c03n3nj0]

sales2099 said:
If the Spanish and portugese never came, then America would have conquered/claimed all of it in the 1800's

Part of me thinks the Aztecs would have kicked the early United State's ass. If they had the chance to have limited interactions with Europeans, giving them just enough exposure to become immune to European diseases by the 1800, the Aztex empire would be all ove Washington's ass with superior numbers and home-turf advantage. That's implying that the U.S. would even go as far down as Mexico back then.