I live in the upper midwest (Chicago). I don’t think it is a matter of Catholics in these regions absorbing the surrounding culture. In most cases, they formed the culture itself.
Chicago’s distinctive culture is almost entirely a result of the Catholics from central and eastern Europe that settled it. Sure we also have Jews, Orthodox Christians, the mainlines, Black evangelicals, but by and large these groups have not affected the overall culture of Chicago–instead each being content to have their own subculture.
There’s a reason why it’s almost instinctive for Chicagoans to refer to a reverend as Father even when he’s not Catholic. It’s because Catholicism has been the dominant religious institution here.
I would not argue with your assessment of culture in Chicago in a general sort of way. Your comments remind me of the chapter in Tom Wolfe’s “Bonfire of the Vanities” entitled “Tawkin’ Irish”. In Wolfe’s tongue-in-cheek, but fundamentally accurate way, he described how Irish influence in New York’s law enforcement establishment sort of “required” everyone, from blacks to Jews to whatever, to “become Irish” because the law enforcement culture had been so pervasively Irish for so long. One even felt obliged to adopt whatever New York ways of speking and acting are peculiar to the New York Irish regardless of one’s real origins. (Thus the chapter title)
Other influences can enter the same cultural stream as one’s religion or ethnicity. As another poster pointed out above, “being Democrat” or “being a union man” was almost identified with being Catholic for a very long time. The cultures sort of melded together at some times in history. My own Irish grandfather, a railroadman, listed three organizations on his “traveling card” (a custom of his time) The Brotherhood of Locomotive Engineers, the Knights of Columbus and the Knights of St. Malachy (an Irish-specific Catholic organization, whose purpose was to encourage non-drinking among its members) The affiliations were unified and tight.
One might be less surprised, today, that 54% of Catholics (Hispanics included) voted for Obama, than that 54% of non-Hispanic Catholics voted against him. 50 years ago, a 54% Republican vote (particularly for someone like McCain) among non-Hispanic Catholics during an economic downturn would have been unheard of.
Cultures can take a long time to change. As the unions have remained joined at the hip with the Democrat party, and the Democrat party has adopted abortion, secular materialism and gender politics almost as the sine qua non of “being a Democrat”, many Catholics seem to have moved with their long-held political affiliations into that same fever swamp, rather than, with their Church, away from it. But that does not mean they never can or never will.
During that part of my life in which I was a Democrat party officeholder, State Committee meetings were almost like school reunions for me. I attended a Catholic college and a Catholic graduate school in this state, and fellow alums were very strong in the party ranks. When the “prolife purge” became stronger and stonger, virtually all of them disappeared from the party activist ranks. I was one of the last to accept the fact that my support of the party and faithfulness to my Church were mutually exclusive. It was a hard thing, particularly since I was unable to become a “true believer” Republican (for various reasons, not important here) and was leaving what, for me, could have been a very nice career track. The same was true of many of my fellow alums; many of whom could claim vastly more credit for making the right choice than could I, since most of them were big city folk who had cultural backgrounds much more similar to that which you attribute to Chicagoans than did I, who came from that part of my state that is Southern in culture.
It’s a lot easier, I think, for a Catholic Southerner to extricate himself from the “Catholic/Democrat” identification than it is for an easterner or a rust belt northerner to do it. I don’t know an enormous number of upper Midwestern non-rust belt people, but I suspect it’s true of them as well.