THE Supreme Court will soon decide whether to hear an appeal in Tuaua v. United States, which poses the question of whether the Citizenship Clause of the 14th Amendment applies to American Samoa. That this is a question at all is puzzling, and not just because it’s called American Samoa.

The 14th Amendment to the Constitution guarantees citizenship to “all persons born or naturalized in the United States, and subject to the jurisdiction thereof.” The United States annexed the eastern half of a group of Pacific islands known as the Samoas at the end of the 19th century. As a result, those islands became American Samoa. Surely, people born in American Samoa are legally speaking born in the United States and therefore citizens by birth. Easy, right?

Not so easy. The answer is that no one knows for sure.

How is it possible that a question as basic as who is a citizen at birth under our Constitution remains unresolved in a place subject to the sovereignty of the United States? To understand, you have to dive into the muck that is the law of the United States territories.

When the United States closed the deal to annex American Samoa in 1899, it left open whether the islands had become part of the United States for purposes of citizenship. The previous year, the United States had defeated Spain in the Spanish-American War and had taken sovereignty over Spain’s former colonies — Puerto Rico, the Philippines and Guam.