But the Party of Lincoln has really become the Party of Reagan in instinct and self-conception. It is ideologically conservative and traditionalist—whereas Lincoln’s Republican Party was the progressive party of its day. It finds philosophical structure in federalism and states’ rights, concepts that comforted southern Democrats of the John C. Calhoun variety. And perhaps not coincidentally, the party’s strongest support now comes from the states of the former Confederacy.

But the most obvious sign that the GOP might have lost Lincoln is the diversity gap between the two parties.