The relationship that many islands in the Pacific have had with the US include a long, painful history that includes military force and colonial expansion. The complicated relationships also led to often confusing citizenship and immigration status laws that determine the voting rights of persons from these areas.
After becoming a state in 1959, people in Hawaii, including of course Native Hawaiians, attained full citizenship rights in the U.S., including full voting rights.
In the case of Guam and the Commonwealth of the Northern Mariana Islands (CNMI), while people from those territories are considered US citizens, they cannot vote in presidential elections because they reside in a territory rather than a state within the US. The electoral college system, the mechanism used to elect the President, does not provide for electoral votes in US territories. However, the national political parties may authorize voters in territories to select delegates in primary elections to represent them at the political party conventions.
American Samoa is in a slightly different position than people in Guam or CNMI. People in American Samoa are US nationals, a status that differs from being a US citizen. Like those from Guam and CNMI, they cannot vote in presidential elections because they reside in a territory rather than a state within the US. But they, like those in Guam and CNMI, can participate in the primary process. And as is the case with Guam and CNMI, they can elect one nonvoting delegate to the US House of Representatives, who is permitted to cast votes in committee and on amendments to a bill but not its final passage.
Another difference between persons from American Samoa and Guam or CNMI is that when someone from Guam or CNMI chooses to move to the US, they can participate in elections once they meet the state’s residency requirement to vote (usually 30 days or less). People from American Samoa moving to the US, however, would have to go through the naturalization process to become a US citizen before being able to vote.
There are other Pacific Island nations that have varying relationships with the US. There are Compacts of Free Association with the Micronesia and Marshall Islands and Palau which give these independent nations certain immigration benefits with the US. Other independent island nations such as Papua New Guinea, Fiji, and Tonga to name a few, do not have any compacts with the US and therefore no special immigration benefits. Whether a compact exists or not, these Pacific Islands are independent nations and their citizens cannot vote in US elections.