Legal immigration has historically been classically liberal and a great boon for the United States.
Immigrants often bring in energy and fresh ideas.
In the past, newcomers from around the world were eager for a second start in the United States. They nearly all worked hard, reminding American-born citizens that that they can never rest on their laurels.
Immigrants honed American competition and helped to keep the nation productive.
Immigrants were typically hyper-patriotic. They reminded complacent Americans how lucky they were to be born in the U.S.