While Indian tribes bordering the United States and Canada may share the same culture, the same ancestry, and even the same name, a descendant of common heritage may not be recognized as “Indian” in the United States, and thus not eligible to receive federal benefits. The federal government has the power to recognize an Indian tribe’s sovereignty and determine who is an “Indian” for tribal services, but limits such recognition to those tribes falling within the geographic limits of the United States. With respect to members of “border tribes” that historically traversed the U.S.-Canada border, “Indian” recognition can be denied to an individual because each federally recognized tribe is subsequently required to limit its membership to those whose lineage can be traced directly to that particular tribe’s location within the United States, regardless of tribal heritage predating the border. The result is a gap in recognition: Many descendants of border tribes are born and raised on one side of the border but only recognized as “Indian” on the other. In the United States, ineligibility for affirmative action—both public and private—is one symptom of this gap in recognition. This Note argues that non-recognition of American Indians for affirmative action purposes illustrates how the federal government’s failure to account for descendants of border tribes prevents the United States from wholly meeting its trust obligation, and proposes ways the government can permanently repair its trust relationship with Indian tribes in this narrow context. It discusses three methods for establishing cross-border affirmative action for American Indians: ratification of a bilateral agreement or enactment of domestic statutory reform within the United States, intertribal recognition of membership between U.S. and Canadian tribes, and a potential short-term solution calling upon private initiatives to embrace a broad cross-border definition of “Indian.” This Note concludes that intertribal recognition is impractical due to existing hostility— both on the part of tribes and their respective federal trustees—to the concept of dual tribal enrollment. Further, while private-sector mechanisms may provide a stopgap solution to the problem, they cannot adequately address the federal standards that perpetuate the gap in recognition. In order to fully cure this defect and fulfill the government’s enduring trust responsibility, Congress must take legislative action to close the gap in recognition and provide equal opportunity for affirmative action to all American Indians in the United States.