The US is not founded on 'someone else's land'. Small portions of the US perhaps, yes, and treaties and courts work through that. Most Indians were hunter/gatherers, and suggesting that because someone roves through massive tracts of land is ownership, is beyond weird.
Seasonal camping sites make sense, more from a 'our land' perspective.
And naturally any signed treaties should be honoured.
You may say "But, they were here first!", yet that's quite false. Native Americans invaded as well, either subsuming or slaughtering existing populations as they did so. Further, Native Americans warred, fought, killed each other, just as Europeans, Middle Easterners, and everyone else on the planet did. After all, human is human is human, and that's (sadly) what humans do.
And if you look at every other country on the planet, the precise same is true. Locals pushed aside as newcomers invaded, whether the UK, Scotland, Russia, Germany, the Middle East, literally every place on the planet.
There is no peoples, no country, no ethic group, which has not over time invaded another.
There is no one alive today, that does not stand on land once called 'home' by another.
You may wonder why I say this, but instead of discussing a land plot inside a Western country taken over by another citizen, you immediately dove into Native American rights and a Middle Eastern conflict for some inexplicable reason.
> Most Indians were hunter/gatherers, and suggesting that because someone roves through massive tracts of land is ownership, is beyond weird.
It is not "beyond weird." It is a well-defended position in contemporary political theory and it has had many prominent defenders for hundreds of years. For example, in the 1790s, Immanuel Kant wrote:
It can still be asked whether, when neither nature nor chance but just our own will brings us into the neighborhood of a people that holds out no prospect of a civil union with it, we should not be authorized to found colonies, by force if need be, in order to establish a civil union with them and bring these human beings (savages) into a rightful condition (as with the American Indians, the Hottentots and the inhabitants of New Holland); or (which is not much better), to found colonies by fraudulent purchase of their land, and so become owners of their land, making use of our superiority without regard for their first possession. Should we not be authorized to do this, especially since nature itself (which abhors a vacuum) seems to demand it, and great expanses of land in other parts of the world, which are now splendidly populated, would have otherwise remained uninhabited by civilized people or, indeed, would have to remain forever uninhabited, so that the end of creation would have been frustrated? But it is easy to see through this veil of injustice (Jesuitism), which would sanction any means to good ends. Such a way of acquiring land is therefore to be repudiated.
Under contract law, should the treaties be honored if the other party weren’t capable of full understanding of what they were signing? I agree with you, but I’m curious to hear your thoughts.