From a distance the teardrop-shaped peninsula looks just like any other bit of the famed Hamptons shoreline. Thick woods crowd down to the water's edge, and through the trees houses and roads can be glimpsed. But this land is not part of the Hamptons, neither is it really part of the United States any more. This patch – in the middle of the playground to Manhattan's social elite – is proudly and fiercely Native American country. Almost four centuries since their first contact with the white man and after a 32-year court battle that has just ended in victory, the...