the only thing that consistently unifies the democrats is what they don’t like
Opposition to Trump is currently the strongest force uniting the Democrats, but I think there’s more dividing the Democrats than just a disagreement about which issues to prioritize.
For example, someone who prioritizes abortion rights usually also supports protecting the environment and vice versa. Most abortion-rights people and environmentalists agree about what the ideal end state is (both goals accomplished). However, someone who supports affirmative action and someone who opposes affirmative action may currently vote for the same candidate but they’re clearly opposed to each other in a way that the abortion-rights person and the environmentalists aren’t. The distinction between liberals and leftists is useful for describing many disagreements of the second sort, and it’s an important distinction because the dividing line between Democrats and Republicans won’t always cut across the same issues it does now.