Please do not dismiss this question out of hand. Think about it a moment. When you say, “I am an American.” what are you saying? We have North America, Central America and South America. When you say you are an American are you thinking about being a citizen of one of the two continents or somewhere in between? Are you thinking about being a citizen of just North America? Generally, when I hear someone say they are American, my assumption is they mean the United States. That is my arrogance.
For several hundred thousand years, beings on the earth thought their clan was the universe. Then they started thinking the flat earth was the universe. Then someone realized the sun, moon and stars were not of the earth and the universe got larger and the earth was the center of it. Then some mathematicians and astronomers began paying closer attention and realized their thinking may need to be adjusted to address the empirical data they were observing. In the 15th century, Nicolaus Copernicus came along and suggested the sun was the center of our solar system in a much larger universe. He was laughed at. Think about what we know now about the universe. The point of this is that in our minds we often see ourselves as the center of the universe.
When I think about where I am and when I say I am an American, I always think the United States of America. Canadians are Americans. Mexicans are Americans. If you are from Nicaragua, you are an American. If you were born in of Rio de Janeiro, you are an American.
If you were born in Mexico and become a citizen of the United States, the terminology we use is Mexican-American. Since Mexico is part of American, the term should be American-American, but that does not make sense. For a while black people were often called African-Americans. Some black people that were born in the United States objected to that terminology, as well they should. Most black people in this country have never been to Africa. If a black person emigrates from Nigeria and comes to the United States and becomes a citizen, do they want to be known as an African-American? Do people that come from England and become United States citizens become English-American or British-Americans. I do not think so.
People used to immigrate to the United States for a better life, because the wanted to be Americans in the United States of America. Today we have many immigrants and refugees in this country that are not American citizens and many are American citizens, but not United States citizens. Some have made it clear they want to be Mexicans in the United States.