From the large 2016 Cooperative Congressional Election Study:
Total fertility rates of non-Orthodox Jews are below replacement. TFRs for the Orthodox are hard to pin down, but they are well above replacement, with estimates ranging from anywhere between 3-8 children per woman. By the time Donald Trump’s Orthodox Jewish grandchildren are his age, Jews will have become a Republican voting bloc!
The conventional take is that because of his rhetorical gestures toward American nationalism and more absurdly his putative vassal status to Vladimir Putin and more absurdly still his alleged “white nationalism” or “white supremacy,” Jews hate Trump. I suspect, though, that in 2020 he will improve on his Jewish numbers in no small part due to demographic shifts in the composition of the American Jewish population. Outmarriage rates for non-Orthodox Jews are high and their fertility is low; outmarriage rates for Orthodox Jews are low (Jared Kushner notwithstanding) and their fertility is high.
CCES variables used: CC18_317(1-2), RELIGPEW_JEWISH