While antisemitism was certainly a factor in formulating this aim, fear of communism and a general fear of poor people in a time of depression were equally influential.
If the Know-Nothings had been more successful, we would've had a much smaller population.
How many attacks have been prevented because the would-be attacker has relatives or business interests in the U.S. who would've been harmed?
And without Einstein and other immigrant scientists, maybe the Soviets would've got the bomb first. And what other inventions were never created, businesses never started, books never written because those Jews died in Nazi ovens?
That presumes that the Soviets were capable of using the same resources equally effectively. They weren't. That's the problem with communism. Once again - and this is something you fail to understand - government is the most important determining factor in technological development and economic success. More important than natural resources or individual minds. Handing the Soviets an Einstein would be like handing a monkey a laptop.
Had the no-nothing isolationists gotten their way, it's entirely possible the U.S. would never have gotten involved in WWI. It's almost certain that we never would have experienced the great depression - the monetary expansion that lead to it being the demand of populists and demagogues. Which would, in turn, have stabilized the global economy. Since WWII was the product of WWI and that economic collapse, it is doubtful that anyone ever would have heard of Adolf Hiedler.
The world is better off because the U.S. is not communist today, and I have to believe that the world would have been even better off if we'd managed to limit that trend even more.
Indeed, it is in part because I think that hard-working, innovative, entrepreneurial immigrants have contributed so much to our culture and economy that I'm so passionate that they be allowed freely to cross our borders.
They have also been the primary contributors of communist and socialist values. We didn't and don't need more immigrants to bring values of hard work and immigration to our shores. Those values already existed in quantity. Is getting a little more of something you already have worth contracting a disease you don't?