The USSC held that the State of Hawaii has used ancestry as a tool for racial definition and racial purpose. Thus, the application of ancestral requisites for the purposes of conferring the right to vote enacts a race-based voting qualification and so violates the 15th Amendment. This instance of voter exclusion was not supported by Morton v. Mancari which allows differential treatment of certain members of Indian tribes. Finally, this criteria for vote was not saved from unconstitutionality because such criteria protected the interests of the OHA trust , its beneficiaries and fiduciaries. Petitioner Rice, a Hawaiian citizen was denied the right to vote for nine trustees to the Office of Hawaiian Affairs (OHA) based on racial disqualification. State law defines two subclasses of Hawaiian citizenry: 1) Native Hawaiians are descendents of no less than 50% indigenous Hawaiian ancestry (races inhabiting the island before 1778), and 2) Hawaiians, all other citizens of the state including those descended from the peoples inhabiting the island in 1778 and thereafter. Thus, this group may include Native Hawaiians of later ancestry. Under state law, the election of trustees to the OHA is a statewide event in which only Hawaiians may vote. Rice, a Native Hawaiian of the first subcategory and therefore denied the vote, sued Hawaiian Governor Cayetano claiming unconstitutionality of the exclusion. A Federal court had granted the state summary judgment in the matter, drawing an analogy between the "guardian-ward" relationship of the state with its Native Hawaiian population and the relationship between the U.S. and Native American tribes. Thus a precedent exists for differential treatment of tribal peoples. Citing Morton v. Mancari (417 US 535), it rationalized the state's responsibility to apply land proceeds to Native Hawaiian programs.
An Appellate court affirmed that the OHA is obligated to Hawaiians by trust of administration and duty, and thus this is the group who should select the trustees who would administer such trust and duty. The USSC overturned this argument.