If you really think about it, America's "success as a scientific powerhouse" owes a significant debt to foreigners: scholars from abroad and workers on H1-B visas.
It has been a well-known fact for decades that white native-born Americans are at a real disadvantage in academia, tech fields, and any sort of research positions, because for whatever reason, the foreigners coming in on H1-B can run circles around them in terms of productivity, innovation, and even sheer numbers.
Perhaps this isn't the sort of "stealin' our jerbs" people first think of, rather than picking strawberries and selling oranges off the 405, but it's a real phenomenon. This is a very prominent reason for skepticism about DEI from the Right, because the outsized influence of foreigners on academia, and by extension STEM and other sciences, has been steadily growing and growing and inflamed by DEI hiring practices in the industries. Essentially, thousands of foreign nationals have been immigrating to the USA to be educated at our best schools, and then exert two-way influence over culture and commerce. Is that a sustainable practice? Is America enough of a "melting pot" that we can withstand that sort of outsized foreign influence within our borders?
Furthermore, America was first in line to embrace Eastern-bloc Jews, from the outbreak of WWI through the end of WWII. Those German and Soviet Jews from the diaspora gained significant prestige, not merely from sympathy or pity, and they now have outsized influence in many Western industries, including Hollywood, finance, manufacturing, and psychology. These are markedly distinct career paths from the ones taken by homegrown Jews, such as the Hasidic ones and other Orthodox communities from New York.
Anecdotally, I too worry about the influx of the dirty Irish into our borders, stealing good jobs and spreading their Irish culture. Oh, sorry, I forgot it's not 1940. In my opinion, America has a strong, strong culture -- brain drained scientist's kids in general look pretty integrated to me, at least the ones I know.
Depends.
If your idea of America consists of just the pre-colonial native groups, Navajo etc., then America was already gone a century and a half ago.
But the America of 1925 had exactly the same arguments about Italians, and of 1845 about the Irish, in that the local born were complaining a lot and didn't trust the newcomers.
The melting pot has been melting for a long time now; you're a big endless stew of a country. (Except for the "real" natives, if there is such a thing).
Actually "Oppenheimer" the movie also supplies examples of two very different New York Jewish backgrounds:
J Robert Oppenheimer, from an affluent, non-religious family - with an Upper West side apartment and a summer vacation home on Long Island. His father came to the USA as a teenager, and prospered in business.
Isidor Isaac Rabi, from an orthodox, Yiddish-speaking family living in a two-room apartment on the Lower East Side. He was born shortly before the family came to the USA.
Did you see the "Oppenheimer" movie? Check the real physicists depicted working on the Manhattan project. A large number of them were European Jews who left before or during the war. Even some others left Europe because of this: Niels Bohr (Jewish Mother) and Enrico Fermi (Jewish Wife).
To be sure there was Wernher von Braun and co as well.
In fact, it would be quicker to list the Manhattan project physicists depicted in that movie who were not Jewish at all:
* Ernest Lawrence