“For most of the twentieth century, American parties were ideological ‘big tents’ each encompassing diverse constituencies and a wide range of political views,”  Levitsky and Ziblatt say on page 168 of “How Democracies Die.” They then assert that the Democratic embrace of the Civil Rights Movement collapsed the big tent. Next, immigrants supported the Democrats, and evangelists supported the Republicans. The result was two tinier tents, one for each party, and each with their own separate audiences.

The point of view here disturbs me. The parties, like sellers in a market, position themselves to win elections like businesses want to win market share. The principal reason that the two parties re-aligned since the 1960s is that the presidential selection system makes the national vote irrelevant. If candidates knew they had to win the national vote in order to become president, then Republican nominees could not have been so willingly insensitive to the desires of black people and immigrants. Nor could Democratic nominees have resisted the concerns of evangelicals. The parties would have needed to create coalitions that could win national majorities, especially in close elections, as opposed to carrying a handful of swing states.

Immigrants did not inevitably support Democrats, and African-Americans famously had long seen the Republicans as the party of Lincoln, the Great Emancipator. These groups did not choose parties so much as the parties chose them or left them. For Republicans, getting the immigrant vote would not help carry California, and the black vote in the old Confederacy could not beat the white vote. For Democrats, the evangelical vote in the Rust Belt, while huge, could not overcome the labor vote.  If the national vote mattered, a different calculus would have prevailed. Both parties would have had motivation to build big tents.