Was there a culture war? Partisan polarization and secular trends in us public opinion

According to many scholars of public opinion, most of the fast-growing divides between Democrats and Republicans over the last few decades have taken place on moral issues. We find that the process of issue partisanship—the sorting of political preferences along partisan lines—properly accounts for public opinion dynamics in the economic and civil rights domains. However, when it comes to moral issues, the prominent change is a partisan secular trend, in which both Democrats and Republicans are adopting more progressive views, although at a different rate. While Democrats are early adopters of progressive views, Republicans adopt the same views at a slower pace. This secular change can be easily (mis)interpreted as a sign of polarization since, at the onset of the process, the gap between party supporters broadens because of the faster pace at which Democrats adopt progressive views, and only toward the end, the gap between partisan supporters decreases.