Persian is relative to Iranian the same way Arab is relative to Iraqi the same way Blacks are relative to Americans the same way Coolie's are relative to Trinnidad etc.
To sum it up, persian is the race, Iranian is the country of citizenship.
Iranians born in America or who have American Citizenship, or who down right want to forget about their life in Iran want to be called Persians because that is their race. Alot of people confuse Persians with arabs because they have the same physical traits and religion, but they dont speak arabic and they have a somewhat different culture.
