What is the USA doing with Samoa? Cut them loose.
Samoa is just raising the offensive/defensive linemen the rest of America won't.
Alternative answer: https://www.cia.gov/library/publications/the-world-factbook/geos/aq.html
Primary reason is noted in the CIA webpage above: best deepwater natural port in the SW Pacific, was strategically important in WW2 and maintained afterwards for that same reason.