On August 1st, 2007, Indigenous nations from within the United States, Canada, Australia, and Aotearoa (New Zealand) signed a treaty to found the United League of Indigenous Nations. The Treaty of Indigenous Nations offers a historic opportunity for sovereign Indigenous governments to build intertribal cooperation outside the framework of the colonial settler states. Just as the Pacific Rim states have cooperated to limit Native sovereign rights and build polluting industries, Indigenous nations can cooperate to decolonize ancestral territories and protect their common natural resources for future generations. The treaty process has involved Indigenous political alliances such as the National Congress of American Indians (NCAI), the Assembly of First Nations (AFN) in Canada, and the Mataatua Assembly (including forty-four Maori tribes) in Aotearoa. The treaty identifies four main areas of cooperation: increasing trade among Indigenous nations, protecting cultural properties, easing border crossings, and responding to the urgent threat of climate change. The Treaty of Indigenous Nations builds a sense of community by including other tribal nations in the community, even those who live on the other side of imposed colonial borders or on the other side of the ocean. Indigenous peoples have survived the effects of colonialism and environmental destruction only by cooperating with each other. It is no longer just a good idea to build these relationships; climate change makes them much more urgent. This article explores some of the relationships being built, or that have the potential to be built, among Indigenous nations, local governments, national governments, and international agencies. (Contains 3 figures and 69 notes.)