From 2016 to 2018, the percentage of voters describing Democratic candidates as “in the mainstream” fell from 48 percent to 33 percent. The percentage describing Democratic candidates as “out of step with most Americans’ thinking” rose from 42 percent to 56 percent.

Over the same period, the evaluation of Republican candidates remained virtually unchanged, 59 percent “out of step” in 2016 and 56 percent in 2018; 31 percent “in the mainstream” in 2016, 33 percent in 2018. In other words, over the past two years voters have become substantially more distrustful of the Democratic Party.

I asked political scientists who study political parties for their evaluation of the dual function of the Democratic Party. Their responses varied widely.

Ryan Enos, a political scientist at Harvard, wrote back to say that one “problem the party seems to have is that it can’t accommodate all social justice demands at once.”

In the 1960s and 1970s, the party became “an advocate for urban areas and racial minorities,” Enos argued, but then

slowly, over time, it has become less of an advocate for rural areas, union members, and other things associated with the white working class. This left a portion of the social justice agenda on the table for another party to capture and part of that capture was the election of Trump.

Morris Fiorina, a political scientist at Stanford and the author of “Culture War? The Myth of a Polarized America,” expressed his substantial agreement in an email:

In my father’s time the modern Democratic Party emphasized reducing economic inequality — making working people better off. Over time the relative emphasis shifted as the importance of inclusiveness/diversity/identity grew. This happened in concert with the rise of a ‘new class’ that was relatively more economically secure and obviously created a more divisive agenda.

Fiorina drew my attention to the book “Rights Talk: The Impoverishment of Political Discourse,” by Mary Ann Glendon, a law professor at Harvard, who, he said, argued

that making so many policy issues into matters of rights and taking them to the courts was counterproductive. It put opponents in the position of denying other people their rights. The latter are more difficult to compromise because if it’s a right, compromise is an abrogation of it.

Fiorina pointed to

the anger my working class steelworker friends expressed about the concept of “welfare rights.” Welfare is charity; no one has a right to it was their view. This was the transformation of an issue that previously would have been seen as an economic redistribution issue into what would be considered a social justice issue.

Fiorina’s example shows how what can be seen as “rights” for one constituency can be seen as “costs” for another.

Fiorina cited the results of the 2016 Voter Study Group Survey of 8000 adults to argue that Democratic elites have adopted a set of issue priorities that are significantly different from those of all voters.

The Voter Study Group identifies 15 percent of voters who fit into what it calls the Democratic-Independent Liberal Elite category. This is the cohort that has often provided leadership for the social justice movement within the Democratic Party. Members of this group have generally been younger, more liberal, better educated and more affluent than average voters.