There are 45 million foreign born in this country not counting their US born children. Why is it surprising that there will be electoral effects? Every year we bring in hundreds of thousands of future Dem voters. Immigrants vote more than two to one for the Dems.
That was the effect that JFK was looking for in the his legislation that was passed after his death, in 1965, to replace the American WASP voters with Catholics and non-WASPs.
JFK (and the left) wanted to import democrat voters to replace Protestants, who had only voted democrat twice before JFKs death, 1932 and 1936, and a group who has only voted democrat once since his death, that was in 1964.
And the people coming into this country largely come from Napoleonic code or other guilty-first legal systems.