The Republican Party, from its formation in 1854, has been built around a core of people considered to be ordinary Americans, but not by themselves a majority. The Democratic Party, from its formation in 1832, has been a coalition of those regarded as out-peoples, often at odds with each other, but together often a majority.Barone sees today’s parties returning to their original roots, the GOP ins vs. the Dem. outs. It’s not a bad hypothesis, people who feel the country is “about” them vs. those who experience it as a bad fit.
Left unsaid is that there is a group of people who sometimes feel “in” and at other times feel “out,” depending on the economy and other issues. These constitute the independents or swing voters courted by both sides.