what is the difference between a us citizen and a national?
U.S. citizens are also considered to be U.S. nationals. U.S. law defines a national as “a person owing permanent allegiance to a state.” Since U.S. citizens owe allegiance to the U.S., they are both U.S. citizens and U.S. nationals. However, it's possible to be a U.S. national but NOT a U.S. citizen.