@solreader50
how things might have turned out without the Manifest Destiny and the genocides that it caused.
Without Manifest Destiny the borders of the USA would be different. The various tribes wouldn't hold any of that land, even their reservations, in the 20th century. The USA was competing with the United Kingdom, the Russian Empire, and the Kingdom of Spain, among others for the land west of the Appalachian mountains. By the 19th century Japan and Germany were in search of colonies. Germany considered war against the USA for control of the Philippines. Japan fought both China and Russia for Korea, Manchuria, and Taiwan; later seizing islands throughout the Pacific (including some from Imperial Germany).
"Genocide" is an even more vacuous claim. Do you "blame" China for the "Black Death" that killed more than 30% of the people of Europe at the time?
The vast majority of tribal peoples of North America who died from c.1400-1900 died from disease. There is significant evidence that fishermen and some merchants from Europe, and possibly Moors too, had contact with various peoples who were living in North America before Columbus set out on his first voyage of discovery.
There is almost no contemporary documentation of these ventures, as they were illegal. Monarchs, or Guilds, or the Hansetic League, claimed jurisdiction off ALL Trade, even if unaware of the Americas. "Vineland" was "known" and a matter of trade disputes between England and the Hansetic League in the 1300's, a sideshow to the Hundred Years War (primarily, but not exclusively between England and France).
Disease was spread by native traders and wanderers. The "mound peoples" and a comparatively extensive farming and crafting peoples west of the Mississippi River, from present day Minnesota to Missouri. Disease wiped out a high percentage of the already scant population of North America before c.1500. Survivors of these settled tribes were wiped out by the Souixian tribes as they expanded south and east.
Mexico is an exception to the rest of North America, for the purposes of the above paragraph. Spanish atrocities throughout Mexico, Central and South America, could be considered genocide. However, utterly unaffected by events in the story, or the comment I am responding to.
From c.1700 to 1900 more of the tribal peoples of North America were killed in inter-tribal warfare, than killed by people of the USA. Disease killed even more. The USA did in some cases try to destroy the culture of many tribes. Not just limiting their hunting and nomadic lifestyle, but also raiding, horse stealing, slavery, etc.
Aspects of the European Enlightenment caused some to question the legitimacy of conquests of land, and forced "resettlement" of most tribes. Such considerations are unique to the USA and Canada, as nearly all other peoples/nations conquer lands and peoples if they are capable. This is a good thing, mostly, that civilized people question wars of conquest, and are revolted by genocide.
I really enjoyed the story. However, I wondered what power would have dominated North America.
The British followed a comparatively enlightened policy in Canada, mostly because they were trying to contain the USA with the minimum cost. The British were stretched beyond thin with their colonies in India, Africa, and elsewhere, as we as adventures and misadventures in China, Afghanistan, elsewhere in Asia and across the globe.
Read about how Spain, Belgium, Germany, Japan, etc. treated the people they conquered in their colonies across the globe.