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Please tell me if there has already been anything covering this, as it seems like it would a a fairly-often-encountered PoD:

Historically, the Lewis and Clark expedition encountered a good amount of friction with the Lakota. What would be the effects of a full-blown conflict early in the expedition in which half of the corps are slain and the other half flee back to Saint Louis? What would be the effects of the expedition perishing entirely, whether from conflict with natives or from disaster in the Rockies?

Furthermore, what would the effects be if the expedition, facing starvation, turned around halfway through the Rockies and returned to tell the tale of there being no Northwest Passage?

In my uninformed opinion, the former might result in a secondary, somewhat delayed expedition in addition to somewhat more genocidal American politics for the early nineteenth century. Total annihilation, especially if the corps died somewhere very remote, might do the same without genocide, in addition to making the secondary expedition somewhat more extravagant. The latter might force the US to cede its claim to Oregon territory, as the Oregon Trail would either be delayed or nonexistent.

So, has this been covered before? If not, who gets Oregon?
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