[inglor_cz]

The 20th century decolonization wars showed that natives can adapt to modern weaponry fairly well.

But you need the numbers to pull this off. Sioux are not numerous enough to threaten American dominance of their territory. If they were as numerous as, say, Punjabis, that would be a different story.

[selimthegrim]

Punjabis acquitted themselves fairly well in 1849.