Gandalf, blood of hobbits on his hands?

[Gordis]

About alliancs. Indeed the only lasting and successful alliance was that between the Gondorians and the Rohirrim. And Andsigil is right :it worked so well because the people in question were alike, were from the same Three Houses of the Edain. Strange no one has posted this quote yet, where Faramir speaks about the Men of Rohan:

And we love them: tall men and fair women, valiant both alike, golden-haired, bright-eyed, and strong; they remind us of the youth of Men, as they were in the Elder Days. Indeed it is said by our lore-masters that they have from of old this affinity with us that they are come from those same Three Houses of Men as were the Númenoreans in their beginning not from Hador the Goldenhaired, the Elf-friend, maybe, yet from such of his sons and people as went not over Sea into the West, refusing the call.
'For so we reckon Men in our lore, calling them the High, or Men of the West, which were Númenoreans; and the Middle Peoples, Men of the Twilight, such as are the Rohirrim and their kin that dwell still far in the North; and the Wild, the Men of Darkness- LOTR "The Window on the West"

So it was much easier for "High" Men, the Numenoreans, to make alliances with their kin, "Middle" Men, than with some "wild" men like the Dunlendings or the Hillmen of Rhudaur, or the Men of the White Mountains.

And even a marriage of Valacar to Vidumavi was frowned upon by the proud Gondorians as a misalliance with one of "lesser" blood. Eventually it led to Kin-strife.
Tolkien was not racist himself, but I am afraid the Numenoreans, both in Gondor and Arnor, were.
Why did the Hillmen of Rhudaur so universally turn against their Dunedain rulers and supported Angmar? Why did Dunlendings follow Saruman? I suspect Dunedain and Rohirrim racism was a huge factor.

For a good alliance there should be mutual profit; mutual, not one-sided. The Men of the Eoteod needed land. Gondor gave them the land, because Gondor had land to spare. Their ancestors had grabbed a huge portion of the West of Middle Earth, but were too sophisticated to keep their own numbers growing. In return for the land grant, the Gondorians obtained all those lances and swords eager to come to their aid at the first call. And to be sure of the Eorling' loyalty Cirion made them swear a quite terrible oath, in the keeping of Eru and the Valar. That alliance was the smartest political decision the rulers of Gondor had ever made - and it worked.

But could they do the same with say, Harad? The Haradrim were even more numerous then the Eotheod, reproducing fast, and always needed more land. Would Gondor grant them these lands in return for the alliance? And to Variags? And to Easterlings? There was not enough land in Gondor to satisfy everybody. And what was on the borders, the "wild" men managed to take without permission.

Also would the "wild" men, who probably had never heard of the Valar, keep their Oath as faithfully as the Rohirrim did?

And then there was Sauron, who was not that bad a ruler after all, if we look at things objectively. And he had already promised the lands of Gondor to the very same peoples - and sorry, was much more likely to grant them to his followers than the Gondorians themselves. Beat that…