The United States Supreme Court has rejected a petition from five American Samoans arguing their case for American citizenship.
Currently, American Samoans are considered US residents, not citizens, which denies the territory and its people several constitutional rights and provisions.
The plaintiffs, led by American Samoan resident Leneuoti Tuaua and a California-based Samoan organisation, complained about not being able to qualify for certain US government jobs.
The case was dismissed by a federal district court in Washington in 2014, which was last year upheld by the appeals court.
The plaintiffs' lawyer, Neil Weare, says they are disappointed with the result, which leaves a constitutional question of tremendous importance unanswered.
In its 2014 ruling, the appeals court held that the citizenship clause of the US Constitution's 14th amendment did not automatically extend to unincorporated territories such as American Samoa and Guam.
The defendants, which included the State Department, argued that only Congress in Washington had the authority to grant citizenship to the territories.
The American Samoa government was also opposed to birthright citizenship, saying unique Samoan traditions may be threatened by a fundamental change in status.
Territory leaders said the citizenship issues was a question for the people of American Samoa and its elected representatives, not the courts, to decide.