From an email from plaintiffs I received:

Tuaua v. United States considers the rights of people born in the U.S. territory of American Samoa, which has been a part of the United States since 1900. Federal law labels the Tuaua plaintiffs as “nationals, but not citizens, of the United States,” making them the only Americans who are not recognized as citizens.  We argue the Citizenship Clause of the 14th Amendment guarantees them birthright citizenship.

One of the most significant impacts of their “non-citizen national” status is on voting rights.  Even though they are American nationals, because they are not recognized as citizens our plaintiffs who live in Hawaii (a veteran) and Washington State are denied the right to vote in state and federal elections unless they first naturalize.  This means that before they can vote they would need to pay nearly $700 in fees and pass an English language and civics test — talk about a poll tax and literacy test!