Aragorn's Reunited Empire: Just a paper dream?

[Kuruharan]

I think Tolkien's view was of a consenting federation.

I think there is a slight misconception of what the Reunited Kingdom was. Aragorn was the (titular) head of a confederation of the Free Peoples. Not all of these were part of the Reunited Kingdom. The confederation and the kingdom were not the same thing. Places like Dale and Erebor, while they acknowledged Elessar as their overlord, were not part of his kingdom in the same way that Bree was.

Inside the kingdom, there weren't really that many different people to be confederated. There were the people of Gondor, the Breelanders, the Shire-folk, the Dunlanders, the inhabitants of Umbar, the Wildmen...and that is about it. The Wildmen and Shire-folk were also explicitly excluded from any federating because they were deliberately isolated from the rest by royal decree.