So, the US passed a few acts to curb European immigration in the early 1900s culminating in a very strict quota system. If this were somehow avoided until the 1960s as it was in much of Latin America, how many people would the US likely take in on net?
How many Holocaust victims would could be realistically spared?
Eastern and later Central Europeans spared from Communist murders and famines?
And how different can the US demographic outlook be?