> USA used to be mostly Northern European and christian (protestant) You are completely ignoring here the huge role that anti-Catholic prejudice had in US hist

> USA used to be mostly Northern European and christian (protestant) You are completely ignoring here the huge role that anti-Catholic prejudice had in US history (and the rest of the Anglosphere as well). Indeed, the vast majority of historic anti-Irish sentiment was really anti-Catholic – "Irish" came to mean "Irish Catholic", and Irish Protestants in the US rebranded themselves as "Scots-Irish" (not only those Irish Protestants who had recent Scottish heritage through the Plantation of Ulster – Irish Protestants who lacked any recent Scottish heritage called themselves that too.)