This paper asks whether history can inform modern debate about immigration's impact on high wage economies. It examines the relationship between migration's labor market impact and capital flows before 1914, the first global era. It then assesses the effects of immigration on wages and employment with and without international capital mobility today, in the second global era. It then explores the links between these economic relationships, welfare burdens, and immigration policy. It concludes with an explanation for the apparent difference in immigration's impact in the two global eras, and thus on policy.