Immigration can be good for you. Yes Winston, those foreigners can in fact help the economy.
Almost a century and a half after the first large migration wave of the late 19th century, those places where migrants settled in big numbers are significantly better off than those which were virtually untouched by the migration wave. Migration is the only factor related to the period of the migration waves which is still strongly connected to current levels of development. Factors such as the level of income of the county at the end of the 19th century or early 20th century, the level of education of the population, the percentage of black population, the participation of women in the labor force, or whether the county was rural or urban – which would have determined the attractiveness of a county to migrants in the first place – have no bearing whatsoever on the current level of development of US counties. While their influence on a county’s wealth and, consequently, on its economic dynamism has disappeared long ago, migration has left an imprint which still affects economic performance.
The above quote is from a working paper When migrants rule: the legacy of mass migration on economic development in the US by Andrés Rodríguez-Pose and Viola von Berlepsch.