Two nations?

 A couple of weeks ago, the New York Times had a piece on the upcoming election that said "Red and Blue Americas are moving farther and farther apart geographically, philosophically, financially, educationally and informationally."  It went on to say "In 1960, about 4 percent of Americans said they would be displeased if their child married someone from the other party. By 2020, that had grown to nearly four in 10. Indeed, only about 4 percent of all marriages today are between a Republican and a Democrat."  I already wrote about the last point.  I think it refers to perceived voting differences from one's spouse (there aren't many political surveys which interview both members of a couple):  they are rare today, but were also rare in the previous years for which I had data (1944, 1960, and 1984).  This post will consider the hypothetical question about a child marrying someone from the other party.  This is a summary of all the relevant questions I could find:

Year                       Positive               Negative             Survey

1960                     14%                       4%                         Almond/Verba
2008                                                     24%                     YouGov               
2010                                                     41%                     YouGov
2014                     28%                       17%                       Pew
2017                                                     14%                      PRRI
2018                     69%                       35%                       PRRI     
2020                                                     38%                      YouGov

The three figures in boldface involve the same question:  the others all had different questions and different response categories.  Some of the surveys just asked one question about marrying someone from the other party, but others asked everyone two questions--one about marrying a Republican and one about marrying a Democrat.  For the ones with two questions, I also show positive responses--people who say they would be pleased if the hypothetical child marries in the party (rather than saying it wouldn't matter to them).  There's clearly been an increase in both positive and negative reactions, although the differences among the questions makes it hard to say much about its exact timing (I wish people had stuck with the 1960 question).

Why do we have stability with (perceived) party differences within actual marriages but increasingly negative reactions to party differences in a hypothetical marriage?  People generally know something about their spouse's political views (although there's undoubtedly a tendency to exaggerate agreement).  But with the hypothetical question, they have to come up with an idea of what an unspecified Democrat or Republican would be like.  The most likely source for that would be prominent Democratic or Republican political leaders.  In a time when ideological differences between parties were small and political leaders tried to show respect for the other side, that wouldn't seem so bad.  But with larger differences and more conflict between the parties, it would.  That is, increased objections to a hypothetical marriage to someone from the other party don't necessarily reflect increased social distance between Democrats and Republicans in the public--they could just reflect increased differences at the elite level.

[Data from the Roper Center for Public Opinion Research]