Josh Marshall has thoughts on Columbus/
I'm old enough to remember when WASP's looked dubiously on Catholics (specifically and especially my mother)--they were subject to the rule of the pope, so weren't fully loyal to the US (somewhat as some even today see Jews and Israel), they were relatively recent immigrants and not fully Americanized.
One Italian-American in my school for a while--don't remember whether Joe was set back or grade or whether he was a grade ahead.--he didn't graduate with us I know that. Pretty good athlete and ran with the jocks. Got teased about being a "wop". At least in memory it was mostly teasing, as we had nicknames for others: "crotch", "piggy", and "spook" were others I remember. The last one wasn't racial--he was very pale.
Italian-Americans were climbing the ladder--Senator John Pastore was prominent as the first senator.
In memory at least JFK's election ended most that that prejudice--the Italians were honorary Irish by virtue of being Catholic, so when he won all the recent immigrant groups won. ("Recent" referring to 30 years before).
Also on immigration--two of the three economics Nobelists announced today are immigrants, which isn't unusual--see this from 2017.