The Immigration Act of 1924 sharply curtailed immigration to the United States. Asians were pretty much banned from entering the USA. Immigrations from Eastern and Southern Europe were effectively banned; their numbers were so small that more people from those parts of the world left the USA than entered. What would the world be like if no Immigration Act of 1924 (or similar law) was passed in the United States?
The one effect I immediately think of is that at least hundreds of thousands, if not millions, of Jews escape Hitler (and the levels of migration stay the same from 1924 until World War II).
The one effect I immediately think of is that at least hundreds of thousands, if not millions, of Jews escape Hitler (and the levels of migration stay the same from 1924 until World War II).