can a us national became a us citizen
Non-citizen U.S. nationals may reside and work in the United States without restrictions, and may apply for citizenship under similar rules as foreign nationals or citizens, except that they do not need to hold U.S. permanent resident status when they apply or to have held it for any length of time before applying. Like permanent residents, they are not currently allowed by any U.S. state to vote in federal or state elections, although, as with permanent residents, there is no constitutional prohibition against their doing so.
United States nationality law