Trump gave his speech the other day, and it is a reminder of the complexity of how we draw lines in political science. Two obvious readings come to mind, and I reference them all the time. One might think they are classics, or something, and that everyone should read them.
E.E. Schattschneider, The Semisovereign People. As a warning, there is a lot that is wrong and outdated about this book, but Schattschneider also did a lot to help us understand the strategic process of drawing lines of cleavage to define political conflict. Much of the conflict in American politics is racial/ethnic. The Republican Party doesn't want to keep it that way. Why? The country is getting less white. Where else could a line of cleavage be drawn? How about between citizens/legal residents, and illegal immigrants? That's the line Trump, and his particular faction of the Republican Party, i.e., not the Chamber of Commerce faction, have been trying to draw for years. That's why George W. Bush, a Chamber of Commerce guy, couldn't get his version of immigration reform, which I addressed the other day.
The logic requires seeing things in terms of strict economic competition. If Latino citizens in low wage jobs see themselves in economic competition with illegal immigrants who take even lower wages to keep things under the table, then a Schattschneider line of cleavage between legal and undocumented pushes Latino citizens into the Trump camp. If they see overcrowded schools in their neighborhoods, kicking out the kids who are illegal immigrants reduces class size for their kids.
The Trump faction (although not Trump himself) has been making this argument for years, not understanding why it hasn't brought Latino citizens into the Republican Party.
So, here's the article I reference more than anything else, and that public opinion scholars reference more than anything else: good, ole' Phil Converse, "The Nature of Belief Systems in Mass Publics." Most people don't think in ideologically coherent ways. A "plurality" of people (more than any other category, but not a majority) think in terms of social groupings. How will this policy affect my group? Those social group identifications are just really hard to change.
And they are socially reinforced by everything from daily life to political events at the national level.
Schattschneider is at war with Converse here, and Converse keeps winning. After the 2012 election, the Republicans understood this. They wrote extensively about it. Converse will continue to win out over Schattschneider.
Does this mean the Republicans are just screwed because of long-term demographics? No. I've tackled this before. The Republicans are probably blowing 2016 by nominating Trump, but the system tends to adjust. Somehow.